Chasing 152, the Super Kings needed 18 off the final over in Jaipur.

But Ravindra Jadeja hit the first ball for six and Mitchell Santner drove the final delivery back over Stokes' head.

Super Kings captain MS Dhoni walked on to the field earlier in the over to argue with the umpires after a Stokes 'no-ball' was overturned.

Dhoni was fined 50% of his match fee for breaking the IPL code of conduct.

Chennai were struggling at 24-4 in reply to Rajasthan's 151-7.

Ambati Rayudu made 57 off 47 balls and India wicketkeeper Dhoni struck 58 off 43 before he was bowled by Stokes off the third ball of the last over.

The next delivery was a full toss to Santner that looked above waist height.

Although umpire Ulhas Gandhe signalled a no-ball, the decision was overruled by square-leg umpire Bruce Oxenford, and an incensed Dhoni returned to the pitch to remonstrate.

All-rounder Stokes also conceded a front-foot no-ball before bowling a wide with the Super Kings needing four from the last ball.

His next delivery was in the slot and New Zealand all-rounder Santner drilled it over long-on to secure a dramatic victory - Dhoni's 100th IPL win as captain.

Stokes was hit for four consecutive sixes in the final over of England's World Twenty20 final defeat by West Indies in 2016.

He took a stunning catch above his head at backward point to remove Kedar Jadhav off Jofra Archer and top-scored with 28 off 26 balls in the Royals' 151-7.

How a dramatic final over unfolded

19.1: Jadeja drives Stokes back over his head for six, with both players falling to the ground

19.2: Stokes over-steps and Jadeja hits the ball through cover for a single

19.2: Dhoni pulls the free hit for two

19.3: Stokes bowls Dhoni with a superb yorker

19.4: Santner picks up two, pulling a high full toss that is initially signalled a no-ball but overturned

19.5: Santner clips towards long-on for two

20.0: Stokes bowls a wide outside off stump

20.0: Santner smashes a full delivery high over long-on to win the match