The New Zealander took 4-28 from his four overs as the Titans kept their opponents well away from their set target of 172.
Their own innings did not get off to the best of starts, with Matthew Wade (1) out in the first over to Mustafizur Rahman as he tried to scoop the ball over his shoulder, but only edging through to Rishabh Pant.
Shubman Gill did lead the way with the bat, though, hitting 84 from 46 balls, accompanied by solid efforts from Hardik Pandya (31) and David Miller (20) as the Titans ended on 171-6 from their 20 overs.
After losing Tim Seifert (3) early on, the Capitals never really looked like reaching the target, with Pant (43) the only man to score more than 25, before he became another of Ferguson's victims.
Delhi suffered their first defeat of the season after only reaching 157-9 from their 20 overs, while Gujarat keep up their perfect start to life in the IPL.
Gill improves on previous outing
Shubman Gill will have been relieved to see his team-mates score the runs to seal the win in their opening game against the Lucknow Super Giants after he fell for a third-ball duck.
However, he more than made up for it here with a tremendous knock of 84, including six fours and four sixes to help his team post an ultimately winning total.
Fergie time for Lockie
Ferguson set the tone by taking the wicket of Prithvi Shaw (10) with his first ball, before also picking up the crucial scalps of Mandeep Singh (18), Pant and Axar Patel (8).
Much like Gill, it was a big improvement from his 0-24 in the Titans' first game against the Super Giants.
Things looked bleak for the Titans when they saw their top order dominated early on, but Hardik's magnificent 87 helped them to 192-4, before the Gujarat attack blitzed their rivals midway through the Royals innings.
Lockie Ferguson and Yash Dayal finished with three wickets apiece as the Royals could only muster 155-9 in reply, sending the Titans two points clear at the top of the IPL table.
The Titans elected to bat after winning the toss but made a dreadful start when both Matthew Wade (12) and Vijay Shankar (2) went early on, the former being run out by Rassie van der Dussen and the latter caught by Sanju Samson.
They steadied themselves to reach 53 before Shubman Gill was dismissed for 11 in the sixth over, before captain Hardik, supported well by Abhinav Manohar (43) and David Miller (31 not out) dragged them back into contention with an outstanding batting display.
Hardik was undoubtedly the star of the show, his 87 off 52 balls almost single-handedly setting a difficult target of 192 as the Royals attack struggled in the absence of fast bowler Trent Boult.
Jos Buttler (52) drove Rajasthan to a decent start with the bat, hitting eight fours and three sixes either side of partner Devdutt Padikkal being dismissed for nought with the very first ball he faced.
Replacement Ravichandran Ashwin went for eight shortly after and the wickets began to tumble in quick fashion once Buttler was finally bowled out by Ferguson, with Samson (11), Van der Dussen (6), and Shimron Hetmyer (29) all walking for the addition of 60 runs.
The below-par Royals eventually lost nine wickets without threatening the target of 193, as Ferguson and Dayal helped themselves to three dismissals each.
Hardik drives Titans with spectacular display
Hardik's brilliant display with the bat drove the Titans to a strong position after a difficult start, falling just five runs short of recording his best IPL showing with a haul of 87.
Debutant Dayal blitzes poor Royals
Three wickets from Dayal on his Titans debut, as well as three from Ferguson, made the win more comfortable than it could have been, with the Royals' final three wickets falling for just 17 runs.
Despite Hardik Pandya (67) racking up another half-century for the leaders, Andre Russell's (4-5) superb late display wrecked the Titans' bottom-order to limit them to just 156-9.
However, Kolkata's attempts to chase down that seemingly achievable target were left in disarray after early exits for Sam Billings (4), Sunil Narine (5), and Nitish Rana (2).
Russell (48) fell just short of a half-century with the bat as he attempted to single-handedly drive his side to victory, but Lockie Ferguson's excellent catch sent him packing in the 19th over and sealed a hard-earned victory for the Titans.
Titans skipper Hardik elected to bat after winning the toss, going on to hit 67 in another outstanding knock as his side targeted a third consecutive IPL win.
Shubman Gill was removed for just seven runs early on, but Hardik's excellent showing led the Titans to 83 before Wriddhiman Saha (25) was dismissed by Umesh Yadav.
David Miller (27) supported Hardik well, but after the duo were caught in the 16th and 17th innings respectively, the wickets fell in rapid fashion as Russell took charge.
He dismissed Rahul Tewatia (17), Abhinav Manohar (2), Ferguson (0) and Yash Dayal (nought) to bag four wickets in a remarkable final over, but a nightmare start to the Knight Riders' own innings saw their hopes of a first win in four IPL matches dissipate.
Billings, Narine and Rana all fell for single figures as the Knight Riders toiled to 16-3, although Rinku Singh's knock of 35 then dragged them back into the contest.
The outstanding Russell then hit 48 off 25 balls to set up tense finale, but was caught by Ferguson two balls into the final over as the Knight Riders fell to a demoralising fourth consecutive loss.
Russell runs riot with the ball, and goes close with the bat
Russell was incredibly unlucky to finish on the losing side, registering a terrific performance with the ball and then almost dragging his team-mates to victory after taking up the bat, only to be felled just two runs short of his half-century.
Hardik show proves vital
Hardik's 67 looked to be in vain for much of the contest, but the skipper's performance eventually proved crucial, accounting for over a third of his team's score before the Kolkata top-order collapsed.
The 31-year-old missed last year's World Cup due to a calf tear and, after a minor abdominal injury, New Zealand head coach Gary Stead has suggested Ferguson could miss the ongoing tri-series in Christchurch.
The Blackcaps are already without Daryl Mitchell after the batter fractured his hand in training on Friday, while spinner Mitchell Santner will join the squad on Sunday after a paternity break.
"Lockie has a little ab injury at the moment. We're just managing that and the most important thing is we get to the start of the World Cup and Lockie is ready to go," Stead said.
"He's a very, very important cog in our bowling line-up. Unfortunately for him, he missed last year's World Cup with the injury he had then.
"I mean we are mindful of it and we want to make sure that he's right and ready for those early games in the World Cup.
"There is that chance [of him missing the entire tri-series]. We will just see how he responds to treatment over the next few days."
Adam Milne is another Blackcaps bowler to suffer from persistent injury issues, with New Zealand aiming to rebuild the 30-year-old's fitness ahead of the World Cup later this month.
"It's the first time I've had eyes live on Milne at the nets and he looked really good," Stead said.
"We're pleased with what we are seeing there and again he is coming off a reasonably extensive injury break as well, so just managing him and making sure he's right will be the most important thing for us in these four games."
While New Zealand scramble for options in their fast-bowling department, Mitchell hopes to be back in action ahead of the first game of the T20 World Cup against Australia on October 22.
"Obviously, not ideal timing, but we've got some good news around where the fracture is in the hand and the time frame to be ready for the first game in Australia in a couple of weeks' time," Mitchell told Spark Sport on the sidelines of New Zealand's tri-series opener against Pakistan on Saturday.
"We'll do everything we can to try and be ready and fingers crossed that I'll be good to go."
In a match interrupted several times by rain, the West Indies lost five wickets for one run but recovered to 180 for 7 from 16 overs thanks to some calculated hitting from their captain, Kieron Pollard.
However, New Zealand replied with 179 for five from 15.2 overs to win by Duckworth/Lewis method.
The home side won the toss and asked the visitors to bat and they obliged racing to 58 without loss in 19 balls courtesy of Andre Fletcher’s 14-ball 34 that included three fours and three sixes.
However, when he was bowled by Lockie Ferguson the second ball of the fourth over, it triggered a collapse wherein the West Indies lost five wickets in 11 balls. Four balls later, he had Shimron Hetmyer caught behind without scoring – 58 for 2.
The West Indies lost two wickets in the following over bowled by Tim Southee, who removed Brandon King for 13 and Rovman Powell without scoring as the West Indies stumbled to 58 for 4. In the very next over, Ferguson trapped Nicholas Pooran lbw for 1 and the West Indies had collapsed to 59 for 5.
Pollard came to the rescue of the Caribbean side as he and Fabian Allen hauled the West Indies to 143 in the 14th over when Ferguson had Allen caught for 30 behind and Keemo Paul out by a similar route without scoring to leave the West Indies 146 for 7.
Meanwhile, at the other end Pollard was at his destructive best, smashing 75 off just 37 balls with four fours and eight sixes to carry the Caribbean side to a competitive total.
Man of the Match Ferguson returned figures of 5 for 21 from his four overs, while Southee took 2 for 22 from 3.
However, the Pollard-led recovery was all for naught as New Zealand, led by Neesham’s unbeaten 24-ball 48 and Devon Conway’s 29-ball 41, propelled New Zealand to 179 for 5 from 15.2overs and the series lead.
Neesham and Conway dragged New Zealand back from 63 for 4 mid-way the seventh over to what turned out to be a comfortable victory. In a fifth-wicket stand of 77 that came off just 34 balls, the pair smashed the West Indies bowling to all parts before Conway fell to Pollard in the 13th over but by then the damage had been done.
Mitchell Santer picked up from there smashing three sixes as he raced to an unbeaten 31 from just 18 balls to secure victory.
New Zealand were aided by poor bowling from the West Indies, especially from Keemo Paul and Kesrick Williams being, who were most culpable. Paul bowled five no-balls while giving up 39 runs from his three overs while Williams’ half volleys saw him being taken for 33 runs from two overs. Allen gave up 32 from two overs.
Oshane Thomas 2 for 23 from three overs was the best of the West Indies bowlers while Sheldon Cottrell returned figures of 1 for 30 from his four overs.
England are down in third in Group 1 with two games to play, dropping below Australia following their defeat of Ireland on Monday.
Jos Buttler's side cannot afford to slip up against the Black Caps, but assistant coach Paul Collingwood believes this to be the sort of scenario in which superstar Stokes thrives.
The Test captain averages just 18.57 in the shortest format and has never hit a T20I fifty, yet Collingwood has no doubt about his ability in "must-win games".
"The one person you want in your team when the pressure is on is Ben Stokes," Collingwood said.
"We all know what he's capable of, and not just match-winning innings, but match-winning innings under serious amounts of pressure.
"If it comes down to the crunch, you want a man like Ben Stokes walking out.
"It's not just what he gives with the bat – the options with the ball and the skill level he brings into the field as well. It's not always just the runs that he makes, but it's everything else that he gives.
"But I'm pretty confident there's an innings just around the corner, and now we're coming into the crucial part of the World Cup, it's almost a knockout stage for us.
"It's must-win games. You always see Ben come to the fore in those situations."
Opponents New Zealand are in a healthier position after two wins from their two completed matches, leading the standings.
But fast bowler Lockie Ferguson knows his team cannot afford complacency as they prepare to face England.
"There's a long way to go for us, and we need to make sure we take it game by game," he said.
"England's going to have a lot of firepower for us that we need to combat in this next game. I'm sure the boys will be up for the next challenge.
"[I expect] what you always expect from England. They come out very hot, they pride themselves on that aggressive nature, and they bat very deep.
"We need to come out with our own brand of aggressive play, but that's not to say it's anything different to what we have done."
