Morgan announced he would be quitting the side on Tuesday, leaving England needing to appoint a new skipper less than four months before the start of the T20 World Cup in Australia.
He skippered England to their first Cricket World Cup title on home soil in 2019, but has struggled for form as of late, with a pair of ducks in their three-match series against the Netherlands earlier this month.
The Dublin-born batter took the armband in late 2014, but admitted the time is now for him to leave his role, with his struggles against the Dutch the final push needed for him to make the call.
"I've been open and honest about when the time would come, over the last three years," Morgan told Sky Sports. "I've engaged a lot with ex-players about when they stopped, how it came about.
"Each person said there's a time and a place when it hits you, or that you wake up and you know, and that moment came for me in Amsterdam.
"I think it's a culmination of a lot of things that over the course of my international career, which has been a long time, I've just come to the end.
"I'm glad I was in a sound enough space to understand that feeling and be aware of what it meant, and also what it means both for the England white-ball side and me in my personal life.
"The day it hit me was quite a sad day, reaching the end of such a special journey. But since that day I've been incredibly proud, content with the decision and excited for English cricket going forward.
Morgan had previously spoken to new England Test coach Brendon McCullum about retirement before, and explained that advice reinforced his decision.
"Baz is one of my close mates," he added. "I've spoke to him about retirement for a long time, and particularly around his, and the transition for him, and he said 'you will know, there'll be a feeling that hits you, just recognise it when it comes'."
Asked if he would like to stay involved in the England set-up, the 35-year-old said: "I think at the moment the best thing is for me to come out of it, let the new captain find his feet, build a relationship with the new coach and ultimately drive towards the next World Cup.
"They come thick and fast, and the potential the team has is unbelievable. I'm excited to sit back and watch, I'm lucky to be a part of such a special time, but I think what's to come might be even more special."
Jos Buttler is tipped to succeed Morgan as captain, with new white-ball coach Matthew Mott previously appointed in May.
A depleted Australia batted first in Lahore, and their total of 313-7 proved beyond Pakistan's reach, despite Imam-ul-Haq making 103.
Head was the main Australian aggressor with a brilliant 101 from 72 deliveries that propelled the tourists to 171 by the time he was dismissed in the 25th over, with captain Aaron Finch (23) having played a supporting role in an opening partnership of 110.
Ben McDermott provided support with his maiden ODI half-century, though Australia lost three wickets for 21 runs in the space of seven overs as McDermott (55), Marnus Labuschagne (25) and Alex Carey (four) fell.
A flurry from Cameron Green, who hit four boundaries in a knock of 40 not out from 30 balls, gave Australia a competitive total to defend.
Fakhar Zaman was dismissed for 18 in the fifth over of Pakistan's reply, but Imam and skipper Babar Azam steadied the innings before the latter was trapped lbw by Mitchell Swepson.
Babar's steady 57 from 72 balls summed up Pakistan's issues, though, with the hosts unable to match the required run rate early in the innings.
Quick losses of Saud Shakeel (3), Mohammad Rizwan (10) and Iftikhar Ahmed (2) further damaged Pakistan's chances, despite Imam's fine work in reaching his eighth ODI century.
Imam's ton included nine boundaries, but he was then bowled by Nathan Ellis, shortly after Pakistan passed 200 with just five wickets down.
Zampa bowled Hasan Ali and Mohammad Wasim to bring up 100 ODI wickets and then moved onto 101 when Khushdil Shah lofted to Carey, with Swepson rounding things off.
Travis makes headway
It took Head just 70 deliveries to reach his second century in a 50-over match, which is the eighth-quickest in the format by an Australian batter, and the fastest against Pakistan by an Australian in an ODI.
His stay came to an end when he hit Shah to Iftikhar, while he also contributed to the bowling attack with figures of 2-35.
Zampa gets his ton
Dropped in and out of the attack by Finch, Zampa bowled superbly to finish with four wickets for 38 runs, becoming the 18th Australian bowler to take 100 ODI wickets.
While the pick of the bunch for Pakistan was Haris Rauf (2-44), Zampa spearheaded Australia as the tourists kept Pakistan's big hitters Imam and Babar – who became the second-fastest Pakistan batter to reach 4,000 ODI runs – scoring at a slow pace.
The hosts made light work of the team at the top of the ICC rankings to get their hands on the Chappell-Hadlee Trophy.
After rallying in the closing overs to reach 195-9 in their innings, Australia rattled through a New Zealand batting line-up experiencing a collective off-day.
This was the second contest of a three-match series being staged in Cairns, and Australia were in early disarray at 26-4 after Matt Henry and Trent Boult each struck twice with the ball. Aaron Finch and Marcus Stoinis both departed for ducks, while David Warner and Marnus Labuschagne made five runs each.
Alex Carey followed for 12 as Mitchell Santner got in on the wickets, before Steve Smith and Glenn Maxwell put on the first substantial partnership, a cautious alliance of 49 for the sixth wicket.
Maxwell (25), Sean Abbott (7) and Smith, whose 61 was the key contribution, fell in quick succession, and when Boult had Zampa caught on the drive by James Neesham, Australia were tottering on 148-9, with six overs remaining.
Mitchell Starc (38no) and Josh Hazlewood (23no) rescued that dicey situation by adding an unbroken 47 for the final wicket, turning the momentum in Australia's favour, and it had swung decisively when New Zealand made their own dismal start with the bat.
The visitors' top order offered feeble resistance, crumbling to 38-5, with captain Kane Williamson top-scoring among those early victims with 17 before being dismissed lbw by a full toss from spinner Zampa.
It was 46-6 when Neesham clipped Stoinis to Finch at midwicket, and 54-7 when Starc had Michael Bracewell caught by a diving Maxwell at gully. Zampa wiped out the tail to complete figures of 5-35.
Boult efforts go unrewarded again
Boult's bowling in his 98th ODI appearance had Australia tied up in knots again, after he took 4-40 in a losing cause in the first match. This time, figures of 4-38 mean he has taken hauls of four or more wickets in consecutive ODIs for the first time in his career.
Again, it was a performance that went unrewarded, with New Zealand left to seek a consolation win in Sunday's final match of the series.Z
Beating the benchmark
Starc took 2-12, while Abbott remarkably finished with 2-1 from five overs, but it was Zampa who brought home the win, prising out Tim Southee, Henry and Boult to complete his five-for. The 30-year-old Zampa posted ODI career-best figures, having previously managed four four-wicket hauls.
Zampa told Fox: "It was a nice night. I didn't bowl my best to be honest. The full toss to Kane, the ball didn't come out as well as I'd have liked, but sometimes it's like that."
Playing down his own performance, he said he "reaped the rewards" after the likes of Starc and Abbott made early inroads, but considered it a victory worthy of celebration.
"It feels good to win any series, but particularly against the number one team in the world," Zampa said. "They're the benchmark at the moment, so it feels good."
Torrential rain, thunder and lightning halted play after 21 overs of the Pakistan innings, with the tourists toiling at 60-6 after bowling Zimbabwe out for 205.
Sean Williams, Blessing Muzarabani and Sikandar Raza each scalped two wickets apiece as no Pakistan batter surpassed the 19 runs managed by Mohammad Rizwan.
The dismal weather would ensure no further play was possible, with Pakistan having completed the requisite 20 overs to ensure a result would be declared, ensuring Zimbabwe won on the Duckworth-Lewis-Stern method.
Richard Ngarava had earlier top-scored for Zimbabwe with a steady 48 off 52 balls, with Raza adding an important 39 from 56 deliveries after the hosts had been dropped to 99-5.
Salman Agha and Faisal Akram finished with three wickets apiece for Pakistan, but it was not enough to prevent Zimbabwe from being declared comfortable victors, with their total some way clear of the DLS par score of 141.
Data Debrief: Zimbabwe end Bulawayo hoodoo
Zimbabwe's victory may not have come in the circumstances they would have envisaged, but it did end their dismal run against Pakistan at Queens Sports Club in Bulawayo.
They had lost each of their previous eight matches against Pakistan at the venue, only winning one of their last nine there overall (one draw, seven defeats), after winning three of their previous four.
They will hope to carry this momentum into Tuesday's second match at the same venue, as they bid to clinch victory in the three-match series.
