Having already clinched the series, England were set a target of 192 at Newlands thanks to unbeaten half-centuries from Faf du Plessis (54 not out) and Rassie van der Dussen (72 not out).
That was the Proteas' highest score of the series but still proved nowhere near enough to prevent England from easing to victory with 14 balls to spare as Malan and Buttler (67 not out) put on a devastating 167.
Coming off a half-century in the second match at Paarl, Malan brutally punished a missed run-out by Proteas captain Quinton de Kock with a magnificent innings, he and Buttler taking turns bludgeoning a South Africa attack absent the injured Kagiso Rabada.
Malan accelerated towards his second T20 international century but, needing two to reach three figures, made the mental error of taking the single that got England over the line, leaving him hanging his head at the end of a remarkable display.
Du Plessis and Van der Dussen were ruthless in capitalising on a disappointing bowling showing from England with their 127-run partnership, which appeared to have lifted the hosts to a strong position as they recovered emphatically from a wobble that had reduced them to 64-3.
They combined for 10 fours and eight sixes in an innings that left Ben Stokes with a bloodied hand after a seemingly innocuous incident at the boundary.
Stokes was not required to bat, however, as Malan and Buttler rose to the challenge with remarkable ease.
Jason Roy (16) was stifled by the South Africa attack, but England soon hit their stride and produced their best powerplay performance of the series - reaching 56-1 in six overs.
Malan should have been run out in the ninth over when he elected to come back for a second, but an outstanding throw from Temba Bavuma was in vain as De Kock fumbled the ball.
That reprieve allowed Malan and Buttler to reach the 100 partnership in 53 balls. Malan needed only 26 to bring up his 50 and Buttler was not far behind - his half-century arriving in 34 deliveries.
It was Malan who took on the mantle towards the end of the innings, however, his fifth six over long-on putting him in striking distance of a hundred that he was denied after his miscalculation left him stuck on 99.
Paceman Malinga has already retired from Test and one-day cricket at international level, yet he intends to lead the team at this year's World Cup, the tournament they won in 2014.
Sri Lanka must come through a four-team group in the first round - playing Ireland, Papua New Guinea and Oman - in order to reach the Super 12 stage.
Malinga is willing to step aside whenever Sri Lanka ask him to, but he wants to see his nation safely through the qualifying stage in Australia.
"I've already retired from Tests and one-dayers," he told a news conference ahead of a T20 meeting with India. "It's [about] whatever is required for Sri Lanka cricket.
"If they say it's enough for me now then I'll be really happy to retire from T20 cricket also.
"But my only target is to be able to play the qualifying [first] round at the World Cup. If I play the qualifying round and the Sri Lanka team qualify for the World Cup, after that, I wouldn't mind any time I retire."
Sunday's opening T20 will see Malinga come up against Mumbai Indians team-mate Jasprit Bumrah.
The India star is the world's top-ranked ODI bowler, but he is making his return from a back injury and Malinga suggests that his lay-off could play in Sri Lanka's favour.
"As the number one [ODI] bowler, he's got the skill and accuracy," the veteran said. "But he's coming [back] after the injury and hasn't played much cricket for five or six months.
"After the injury, most of the bowlers struggle for the first few matches. We want to make that an advantage for us."
Markram this month replaced Temba Bavuma as captain, with the Test and one-day international skipper axed from the T20I squad.
The opener at SuperSport Park will also be the first T20I since Rob Walter took over as white-ball head coach and comes on the back of a 1-1 ODI series draw with the Windies.
Markram was given the honour of captaining his country in only his third ODI back in 2018, when Faf du Plessis was absent along with other senior players.
The batter felt that opportunity came too soon and believes the experience he has gained since then should stand him in good stead.
He said: "I was quite fresh back then. I was very hard on myself, and always wanted to do well and we know this sport, it doesn't always work out that way."
Markram added: "Being with the legendary team the Proteas had at the time, I paid attention to how Faf managed to marshal his troops.
"That is something I looked up to and strived for probably without him knowing, it was just through me observing from the side."
It will also be a special weekend for Powell in Centurion, where there will be a double-header before the series ends with a contest at JB Marks Oval Potchefstroom on Tuesday.
Powell was selected as the man to replace Nicholas Pooran, who stepped down after the T20 World Cup in Australia last November.
South Africa will be looking to take the momentum from a record-breaking series-levelling ODI win over the Windies in which Heinrich Klaasen was the star of the show.
Klaasen struck 119 off 61 balls as the Proteas chased down their victory target of 261 in just 29.3 overs in Potchefstroom, becoming the first team to score 250 or more to win in under 30 overs.
De Kock set to move level with De Villiers
Wicketkeeper-batter Quinton de Kock is set to go joint-third on the list of the highest appearance-makers for the Proteas in T20Is, as he is currently one behind AB de Villiers' tally of 78.
De Kock has enjoyed facing West Indies in the shortest format, scoring half-centuries in each of his past three knocks.
Windies away form must be addressed
West Indies have won only one of their past 15 T20Is on tour, that coming against Zimbabwe last October.
Facing South Africa could present a good opportunity to address that poor record, as the Proteas have lost four multi-game bilateral T20I series at home – that is their longest losing run in this format.
Led by Aiden Markram's excellent 48 from 33 balls, the Proteas were on dominant form in Colombo, successfully defending their 163-5 total.
Making his T20I debut, South Africa captain Keshav Maharaj won the toss and chose to bat, with his openers swiftly proving that decision correct.
Quinton de Kock (36) set the tone with a boundary off the second ball and Reeza Hendricks soon skittled off 12 runs in the space of three deliveries to get South Africa up and running.
Both openers had moved into the 30s by the ninth over, though De Kock was the first to fall when he sliced a sweep to deep midwicket.
Wanindu Hasaranga picked up his and Sri Lanka's second wicket in his next over, dismissing Hendricks for 38, but Markram – with support from David Miller (26) – put South Africa back on the front foot.
Markram fell just short of a half-century in the penultimate over, though the damage was done as South Africa set a challenging target of 164.
Sri Lanka started their chase confidently, and had 34 runs in the bank by the time Avishka Fernando succumbed in the sixth over.
Yet Maharaj's first ball in a T20I brought up the Proteas' second wicket – Bhanuka Rajapaksa going for a duck – and the hosts failed to keep up the run rate.
That was despite the best efforts of Dinesh Chandimal, who top-scored with 66 not out, but Chamika Karunaratne (22no) was his only team-mate to make it above 20 as Sri Lanka were limited to 135-6.
Memorable debut for Maharaj
Installed as captain on his maiden T20I appearance, the spinner took a wicket with his very first ball, after South Africa's batsmen had shown just why the 31-year-old was right to bat first.
Maharaj has plenty of international experience, with 36 Tests and 14 ODIs under his belt, and in total he has now taken 149 wickets for his country.
Chandimal cannot carry Sri Lanka
It was a valiant effort from Chandimal, whose unbeaten 66 included five fours and two sixes. However, he did not have the necessary support from the rest of Sri Lanka's batsmen, with two going for ducks and Dhananjaya de Silva only scoring one.
Chandimal did bring up his highest score in his T20I career, though, with the wicketkeeper's previous best having been 58, a score he made twice in 2016, against Pakistan and Australia.
The Proteas are in the midst of their all-formats tour of England, and after beating Jos Buttler's team in a three-match T20I series, they face an Ireland side that is still winless in a T20I series under new coach Heinrich Malan, who goes up against his home nation.
Ireland came close to famous wins against both India and New Zealand, but they have lost their last six T20Is, which is tied for their longest losing run in the format, while they have already suffered defeat in eight T20Is in total this year.
South Africa played Ireland in 2021, drawing an ODI series but comfortably winning the three T20Is.
Markram, however, is not taking anything for granted ahead of Wednesday's opener in Bristol, as South Africa look to gear up for this year's World Cup, with the Proteas only playing India in the shortest format in between this series and heading to Australia.
"It will definitely be a new, exciting challenge for us," he told reporters. "We played them quite recently in Ireland and we saw exactly what they could do.
"They are improving series by series, we saw them against India, and they are a team you can't take for granted."
South Africa do not go into this with their first-choice squad, with injuries to captain Temba Bavuma and paceman Kagiso Rabada.
Markram though is among the players eager to stake a claim ahead of the World Cup.
"The communication has been really good from coach, management team and captain," said Markram, who has been the top scorer for South Africa in eight T20Is since the beginning of 2020.
"It makes it easier to understand why they are [rotating players]. Building up to World Cups you want to pick your best squad and it's important to give guys fair opportunities before you select the team."
Tector tipped to flourish
Harry Tector is likely to be key for Ireland. He is reportedly drawing interest for Cricket South Africa's new T20 league, meaning he has a real chance to impress any would-be suitors, having scored 384 runs across 14 ODIs at an average of 76.40 this year, and 249 in nine T20Is.
Tector said: "We've shown that when we stand up to these teams, we are capable of going blow-for-blow with them, and it feels that way within the group. The belief is there that we can beat these big teams, and not get nervous about any team we play."
Catching practice required
Since the beginning of 2021, no team has dropped more catches in men's T20Is than South Africa (40), who have managed a catch success rate of 79 per cent during this period
Quinton de Kock does not buck that trend, as since the start of 2020, he has dropped more catches than any other wicketkeeper.
Mitchell Marsh will return to the batting order when Australia step up their T20 World Cup preparations against West Indies on Wednesday, captain Aaron Finch has confirmed.
Meanwhile, Marcus Stoinis is expected to return for Sunday's opening T20I against England, having joined Marsh in missing the recent tour of India.
Marsh has not featured since an ODI outing against Zimbabwe in August after sustaining an ankle injury, leaving Cameron Green to deputise throughout last month's 2-1 series defeat in India.
While Marsh will not bowl against the Windies, Finch believes a place at number three is his to lose, saying: "One-hundred per cent, he's made that spot his own in T20 cricket.
"I think the way that he played in the lead-up and then through the World Cup [last year] is so important for the way that we want to play and gives us a lot of flexibility through that middle order.
"I think he had his second bowl yesterday and he felt really good. He pulled up well from it. So that's a really positive sign.
"I think for the balance of the side, it's better when they [Marsh and Stoinis] are both bowling because you can get caught a little bit short if you go in with five bowlers. But we'll work that out."
Having suffered a side strain in early September, Stoinis has not travelled to the Gold Coast for Australia's meetings with the Windies, but will join the squad in Perth for the first of three matches against England.
Finch is hopeful over Stoinis' fitness, highlighting the role of logistics in that decision as he added: "He's at a level where we think that he'll be fully fit for that first game against England.
"We were just conscious of the travel with a quick turnaround. It can be quite a high-risk game for some guys with some soft tissue injuries so he's just still planning and preparing there.
"He's such an important part of our side and the make-up of it, especially with his bowling."
While Green performed well in India, recording scores of 62 and 52, Finch doubts whether he can force his way into Australia's 15 for the World Cup if Marsh and Stoinis stay fit.
"I don't think so," Finch added. "It's just one of those things. He had a really good tour of India. It was good for him to get an opportunity to open the batting.
"I think he'll get an opportunity at some point in this series. Obviously his batting is exceptional and he shows a lot with the ball.
"He keeps improving every time he gets an opportunity but over the next few weeks, he'll get a run, no doubt."
Australia begin their World Cup defence against neighbours New Zealand on October 22
A competitive England score had been chased down in the opener, meaning the world champions were in trouble again when they could only tally 117 on Sunday.
Jos Buttler's tourists slowed alarmingly after reaching the end of the power play on 50-1, crucially losing Phil Salt (25 off 19) in the seventh over before Mehidy Hasan came to the fore for Bangladesh.
Mehidy finished with figures of 4-12, and he then had a key role again with the bat after England had threatened to come back into the match.
Although the Bangladesh reply saw only 32 runs scored in the power play, they still required just over a run a ball at that stage to make 118 – an increasingly achievable target when Mehidy scored 20 off 16, including two sixes.
That contribution would prove decisive – along with a steadier 46 from Najmul Hossain Shanto – as the chase was completed on 120-6 with seven balls remaining, sealing the series ahead of Tuesday's final match.
England stutter after solid start
All out for 117 from the final ball of the innings, England went from a run rate of 8.33 in the power play to 4.79 across the remaining 14 overs.
Even on a difficult pitch, that score – England's eighth-lowest in T20Is – was never likely to be quite enough.
Mehidy makes the difference
Mehidy had career-best figures with the ball, removing Moeen Ali for 15 and then bringing out the tail with the consecutive wickets of Sam Curran, Chris Woakes and Chris Jordan.
But his brisk knock with the bat was every bit as vital, with only Salt, Mehidy and Taskin Ahmed (a late eight off three) scoring at more than a run a ball in the match.
Heinrich Klaasen blasted 66 from only 33 balls after Temba Bavuma (49 off 24) and Quinton de Kock (35 from 24) laid the platform for the Proteas, who posted an intimidating 222-6 at Centurion on Sunday.
England embraced the challenge of pulling off their second-highest successful run chase in the shortest format to turn the series around, Morgan making an astonishing 57 off 22 deliveries as they got home with five balls and five wickets to spare.
Captain Morgan struck seven sixes, equalling the England record of a 21-ball fifty that he set against New Zealand last year, after explosive knocks from Jos Buttler (57 from 29) and Jonny Bairstow (64 off 34).
There were 28 sixes in a contest which proved to be a batsman's paradise at altitude, with England ending a successful tour on a high note after also coming from behind to secure a 3-1 Test triumph and draw the ODI series.
De Kock capitalised on winning the toss by delivering a brutal onslaught along with Bavuma, the openers needing only 22 balls to get 50 on the board.
The captain disdainfully hammered Chris Jordan for three consecutive sixes, with Mark Wood also given the treatment before De Kock struck Ben Stokes (2-35) to Bairstow in the deep.
Bavuma drilled Adil Rashid's first ball over the rope, but the spinner got a measure of revenge when he bowled him one short of a half-century and Stokes struck again to see the back of Rassie van der Dussen.
Klaasen, in for JJ Smuts, then took centre stage, racing to a half-century in 25 balls, with 23 runs coming off an over from a struggling Wood.
David Miller made only nine in a fourth-wicket stand of 66 with Klaasen, whose scintillating knock was ended by Tom Curran (2-33), but his unbeaten 35 got South Africa up to their fifth-best T20 total.
In England's response, a fine catch from Tabraiz Shamsi sent Jason Roy on his way in Lungi Ngidi's second over before Buttler set about the returning Dale Steyn and took only 23 deliveries to reach his half-century.
Bairstow also looked ominous, dispatching Shamsi and Bjorn Fortuin into the crowd as the 100 mark came up inside nine overs, but Buttler gave it away when he was caught ramping Dwaine Pretorius.
The clean-striking Bairstow was bowled by Andile Phehlukwayo, having nailed three sixes, and England needed 78 from 38 when Dawid Malan - replacing the unwell Joe Denly - edged behind in a superb over from Shamsi.
Morgan middled Pretorius over the fence twice in the next over to silence the crowd and did the same to Ngidi after ending Steyn's spell with a six.
Stokes launched Phehlukwayo for back-to-back sixes before an incredible stand of 61 off 4.3 overs was ended when he holed out to Ngidi.
An imperious Morgan struck another two sixes in that same penultimate over from Ngidi, and Moeen Ali struck the winning runs after both he and the skipper offered chances to Pretorius.
Phil Whitticase returned the positive result following a PCR test administered on Friday at the Ageas Bowl in Southampton.
He will now observe a 10-day period of self-isolation from June 25 in accordance with the UK Government's protocol on quarantine, a statement from the England and Wales Cricket Board (ECB) said.
The ECB also confirmed seven other members from the match officials and anti-corruption unit teams were deemed to be close contacts, including five people who were due to officiate at England's first ODI match against Sri Lanka in Durham on Tuesday. They will also have to self-isolate for 10 days.
No members of the two teams were impacted, according to the ECB, which said alternative arrangements will be put in place to ensure Tuesday's ODI goes ahead as planned.
The hosts elected to bowl first and, despite being without rested trio Josh Hazlewood, Pat Cummins and Mitchell Starc, restricted their opponents to 139-8 off their 20 overs.
Opener Pathum Nissanka top-scored with 46 off 40 balls, while Kusal Mendis added 27 off 21, but it was another underwhelming batting display from the tourists.
Jhye Richardson impressed with figures of 2-20 off his four overs, paving the way for Australia to make it nine T20Is without defeat against Sri Lanka, winning eight of those.
That is despite getting off to a slow start to their response as openers Ashton Agar and Ben McDermott made 19 off 25 balls, before the latter (nine) fell to Maheesh Theekshana.
Aaron Finch was snared by Danushka Gunathilaka for just two runs off the bowling of Lahiru Kumara and Agar (26) was next to go when he top-edged to Mendis.
But star man Glenn Maxwell and Josh Inglis all but ensured there would be no joy for Sri Lanka with their fourth-wicket stand of 71 off 47 balls.
Inglis went for 40 off 20, leaving Australia needing 20 off 22, and Maxwell got them over the line with his unbeaten 48 to set up a potential whitewash in Sunday's fifth match.
MCGlee for Maxwell
Australia have now won five of their last seven T20Is at the MCG, including the last three in a row – their best run since winning four in a row between 2008 and 2011.
Agar's struggles as a makeshift opener will be of concern, but Maxwell's 48 off 39 balls – a strike rate of 123.1 – meant Sri Lanka's modest target was never of concern.
Pathum shows more promise
Nissanka headed into the game as the only player to score above 100 runs this series against Australia (125) and the 23-year-old was again Sri Lanka's shining light in the fourth T20I.
He helped steer his side to 73-1 at the halfway mark alongside Mendis, yet the tourists still managed to squander a promising opportunity.
Opener Finch was dismissed without scoring in the second and third ODIs as the tourists suffered a 2-1 loss to a Babar Azam-inspired Pakistan side last week.
The skipper has not scored an international half-century since last July, but Australia interim head coach McDonald says he remains the man to lead his country when they attempt to defend their T20 World Cup title on home soil.
"From my end, there's no conversation around the [prospect] that he won't be there," said McDonald.
"His form can ebb and flow – like most players' can – and his ability to work through these patches has been significant in his career.
"We had the same conversation about David Warner leading into the T20 World Cup last [year], so all these conversations are going to happen.
"Do we think he's still good enough to play this level? One hundred per cent yes. That's as simple as it gets for us and we're building a team around him as captain.
"It's a pretty significant pillar to be discussing about not being at the T20 World Cup. From our end, we think he can still play at this level, 100 per cent."
Finch will be one of only three players who are set to face Pakistan in Lahore that were part of the side that won the World Cup in Dubai last November.
Australia will be looking for a fourth consecutive T20 win over Pakistan, but they will have their work cut out as the hosts have come out on top in 10 of their past 11 home matches in the shortest format.
Babar a class apart
Captain Babar made back-to-back centuries to give Pakistan a first ODI series win over Australia for 20 years.
The irrepressible skipper has made a staggering three hundreds, as many half-centuries and 36 in his past five knocks for his country - demonstrating his class in all formats.
As the top-ranked player in the world in both white-ball formats, Australia must find a way to remove Babar before he is set.
McDermott and Head vying for opening spot
Either Ben McDermott or Travis Head look set to open with Finch in the only T20 match before Australia head home.
There was good news for the tourists when Ashton Agar and Josh Inglis returned negative COVID-19 tests, while Marnus Labuschagne and Cameron Green are in contention to make their T20I debuts.
Opener Mendis carried his bat, hitting five fours and a six off 58 deliveries as Sri Lanka reached their 155 target with just a ball to spare at the MCG.
Captain Dasun Shanaka made a valuable 35 off 31 before departing to Kane Richardson in the final over, while Charith Asalanka made a swift and important 20 off nine.
Earlier, Australia had posted 154-6 having struggled with the bat early in the innings, Matthew Wade top scoring with 43 not out.
The hosts defended pretty well but ultimately did not have enough runs on the board to secure a clean sweep of the series.
AUSSIES SLOW OFF THE MARK
Australia will defend the T20 World Cup on home soil later this year and have used this series to experiment with a few ideas.
On this occasion here, they struggled to get going with the bat and lost openers Aaron Finch (8) and Ben McDermott (3) cheaply.
Josh Inglis (23) and Glenn Maxwell (29) made starts without posting big numbers and had Wade - who had two fours and two sixes in his 27-ball knock - not contributed then it would have been an even tougher outing.
MAGIC MENDIS
One of the key difference makers was Sri Lanka's aggression in the powerplay. The tourists hit 54 runs for the loss of two wickets, compared to Australia's 22.
Asalanka's cameo certainly gave Sri Lanka momentum, but Mendis earned Player of the Match recognition for a fine performance.
The players were in Durham preparing for the first of three ODIs against the world champions last month when they left the team hotel to visit the city centre despite strict COVID-19-related rules.
Batsmen Mendis and Gunathilaka and wicketkeeper-batsman Dickwella were sent home and have now been hit with strong sanctions.
The executive committee of Sri Lanka Cricket took into account recommendation made by an independent panel of inquiry before handing down a 12-month ban from playing at international level and a six-month domestic suspension.
They were also given a further one-year ban, which is suspended for a two-year period.
Mendis, Dickwella and Gunathilaka have been fined 10million Sri Lanka Rupees (around £36,000) for their indiscretion.
Ishan Kishan (76) combined with Shreyas Iyer (36) in a destructive 80-run partnership as India posted 211-4 – the highest score in T20Is at the Arun Jaitley Stadium in Delhi.
That total was boosted by a late flurry of runs from Rishabh Pant (29 off 16 balls) and Hardik Pandya's 12-ball 31 for a much-changed India, without Rohit Sharma, Jasprit Bumrah or Virat Kohli.
South Africa soon lost captain Temba Bavuma (10) in the chase, caught behind off Bhuvneshwar Kumar (1-43), before Dwaine Pretorius and Quinton de Kock offered brief resistance.
Harshal Patel (1-43) then removed Pretorius (29), and De Kock (22) followed to Axar Patel (1-40), with South Africa 81-3 after 8.4 overs, before Miller and Van der Dussen joined in an incredible 131-run partnership.
Miller blasted 64 off 31 and Van der Dussen – dropped on 29 by Iyer – mustered 75 off 46 deliveries to complete the sixth-highest run chase in T20I history and take a 1-0 lead in the five-match series.
India run ends
India seemed set to move clear of Afghanistan and Romania (both 12) for the longest winning streak in the format's history and end South Africa's own four-game winning run.
But the late heroics of Miller and Van der Dussen ensured South Africa collected their 12th win in 13 T20Is, while India have won just one of their past five at home to the Proteas in 20-over cricket.
Maharaj misery in winning cause
Maharaj picked up the all-important wicket of Kishan, but the left-armer struggled against India, albeit in a winning cause.
He went for 43 from his three overs, at an economy of 14.33, but could have been helped by De Kock had the wicket-keeper not missed a stumping of Iyer on 25.
Batsman Shafiq was on Wednesday omitted from a 35-man squad to face the Black Caps after a poor Test series in England.
Mohammad Amir and Shoaib Malik were also omitted from a touring party for three Twenty20 Internationals and two Tests against the Black Caps in December and January.
Uncapped Paceman Amad Butt, batsmen Danish Aziz and Imran Butt were included along with Rohail Nazir as the Pakistan selectors invested in youth.
Pakistan head coach Misbah, who named Mohammad Rizwan as Babar Azam's Test vice-captain and Shadab Khan as T20 deputy, says there can still be a way back for the 34-year-old Shafiq.
He said: "There are three major omissions from the side that toured England. Asad Shafiq has been left out due to lack of form after he managed 510 runs in his last 15 innings, including a total of 67 runs in England.
"Asad is an experienced batsman and I am sure he will utilise this time to work harder on his game in the domestic first-class matches so that he, like Sarfraz Ahmed, can reclaim his form and be back in contention for the upcoming Tests against South Africa and Zimbabwe.
"Shoaib Malik and Mohammad Amir are not part of the white-ball matches as for this tour we have opted to invest, develop and focus on the promising and emerging players who are likely to be available to Pakistan for all formats."
The first T20 will be staged at Eden Park on December 18 and the Test series gets under way at Bay Oval, Mount Maunganui on December 26.
Pakistan squad:
Abid Ali, Abdullah Shafique, Fakhar Zaman, Imam-ul-Haq, Shan Masood, Zeeshan Malik, Babar Azam (captain), Azhar Ali, Danish Aziz, Fawad Alam, Haider Ali, Haris Sohail, Hussain Talat, Iftikhar Ahmed, Imran Butt, Khushdil Shah, Mohammad Hafeez, Mohammad Rizwan, Rohail Nazir, Sarfraz Ahmed, Imad Wasim, Shadab Khan, Usman Qadir, Yasir Shah, Zafar Gohar, Amad Butt, Faheem Ashraf, Haris Rauf, Mohammad Abbas, Mohammad Hasnain, Mohammad Musa, Naseem Shah, Shaheen Shah Afridi, Sohail Khan, Wahab Riaz.
The former Pakistan batsman must quarantine for 10 days after he was the only member of the touring party to return a positive PCR test.
Misbah had been due to head home a day after Pakistan salvaged a 1-1 Test series draw with West Indies, winning by 109 runs at Sabina Park.
A Pakistan Cricket Board (PCB) statement said: "Pakistan head coach Misbah-ul-Haq has tested positive and, as such, will not depart for Lahore with his side later today (Wednesday).
"Misbah, who is asymptomatic, will now undergo a 10-day quarantine, following which he will depart for Pakistan.
"Misbah was the only Pakistan squad member who failed two pre-departure PCR tests. All other members will leave Jamaica as per schedule later today.
"The PCB is constantly in touch with Cricket West Indies who have confirmed that Misbah will be shifted to another hotel for the 10-day quarantine with a medical specialist assigned to look after his health and wellbeing."
Pakistan's next assignment is a home ODI series against New Zealand next month.
Former Pakistan captain Misbah was appointed as head coach and chief selector in September 2019.
The 46-year-old will continue to carry out selection responsibilities until a new chief selector starts work on December 1.
Misbah's decision to concentrate solely on his coaching role may have come as a result of the introduction of a new Pakistan Cricket Board (PCB) code of ethics, which was ratified in July.
That code aims to put greater emphasis on resolving issues of conflict of interest.
Misbah told PCB chief executive Wasim Khan in Islamabad last week during the National T20 Cup that he no longer wishes to head up the selection panel.
He said: "I have thoroughly enjoyed the dual roles but after reviewing the past 12 months and looking ahead at the workload in the next 24 months of my tenure, it is appropriate that I invest and dedicate all my time, energy and attention to one role from now on.
"Coaching is my passion and my ultimate objective remains to contribute to the development of players and help the side achieve bigger successes. When I was appointed last year, I was offered the coaching role first and then given the option to also head the selection committee, which I had graciously accepted.
"I am grateful to the Pakistan Cricket Board for their understanding and for supporting my thought process."
Jos Buttler's side became the first team to be both T20I and 50-over world champions at the same time with a five-wicket victory over Pakistan in the final at the MCG on Sunday.
After playing seven World Cup matches in a period of just over three weeks, England will remain in Australia for a three-match ODI series that starts at Adelaide Oval on Thursday.
Moeen is among nine members of the T20 World Cup squad who will face Australia, but the all-rounder feels they should be taking some hard-earned time off.
"It's been happening for a while," he said. "As a group we want to enjoy and celebrate and have that time because you put so much into it as well. It's not just while the tournament is going on, there's the pre-tournament, the build-up and all that.
"Having a game in three days' time, it's horrible. As players we're kind of getting used to it now. But to give 100 per cent all the time is difficult when you're playing every two, three days.
"We have to do it and while we're here we might as well do it, it would be better than going back and then having to come back out another time."
England white-ball head coach Matthew Mott also feels the schedule is asking a lot of the players.
"We always saw that series as being something that we will have to be really professional about," said Mott.
"Cricket is a funny game: we have long breaks off in the white-ball game but when we're on, we're on. We've got to enjoy this victory, they don't come around very often so there'll be no disguising the fact that we will enjoy this.
"But come game day, we've got to turn up and make sure we put out a great effort. For the white-ball team in particular, we get through those three games and then there's a long break. So that'll be the time to properly let the hair down and enjoy it, but the schedule is the schedule and we've got to move with it."
Moeen, who has previously filled in as England's captain in T20Is and was named as vice-captain for the tour of West Indies earlier this year, retired from Test cricket in 2021.
The 35-year-old wanted to focus on the limited-overs formats, and more players seem to be faced with the decision of sacrificing one for the other.
In part, this has been put down to the tight and congested nature of the cricketing calendar, with tours scheduled between high-profile tournaments such as the Indian Premier League, the Big Bash League and, in England, The Hundred. There is also the small matter of another T20 World Cup coming up later this year in Australia.
England's new Test captain Ben Stokes has made a similar decision, giving up white-ball cricket to focus on the long format, while he skipped The Hundred alongside team-mate Jonny Bairstow this year.
"At the moment it's not sustainable," Moeen told reporters when asked about his concerns over the schedule.
Moeen also believes that 50-over matches are most vulnerable.
"Something has to be done because I fear losing the 50-over format in a couple of years because it's almost like the long, boring one," said the all-rounder, who is the captain of Birmingham Phoenix in The Hundred.
"There's no importance given to it at the moment.
"International cricket in all three formats is by far the best cricket to play, but I do worry there are so many tournaments out there that players are retiring more now, and you'll see more retiring soon, because of overlapping schedules."
Mark Wood (3-20) removed half of Pakistan's top six as England bowled out the hosts for 145 runs in 19 overs in Lahore, a reasonably low score considering Mohammad Rizwan top-scored with 63 off 46 balls.
However, England were unable to chase Pakistan's total down despite Moeen making a half-century off just 35 balls, not aided by finding themselves 31-3 after five overs.
And Moeen was frustrated with his team's display, telling reporters: "Of all the games so far, this was the most disappointing, the way we batted in particular.
"Obviously I'm disappointed we didn't chase those runs. I feel we're a better team than that. You have to see the situation of the game, and the conditions.
"All we needed was one partnership, a 60-70 run partnership would have won the game. We want to play this brand that is attacking but you also have to see the situation of the game and the conditions, things like that."
Moeen also spoke of his admiration of Rizwan while also reserving praise for Pakistan's debutant seamer Aamir Jamal, who bowled superbly in the last over to restrict England to seven runs when 15 would have won them the match.
"He's [Rizwan] a brilliant player, so hard to stop and so busy. He's somebody we can learn a lot off," Moeen added.
"He saw the situation and adapted today. He took the risks when he needed to and played properly when he needed to.
"[Jamal] was on debut, nervous, but he bowled really well.
"Two big hits and you’re done. I got one but unfortunately couldn't manage to get the other one. Sometimes you've just got to give it to him, it was a good last over."
