Having been put in to bat in front of their home crowd, the Super Kings posted a total of 192-5 in their 20 overs.
Sanju Samson, coming off a century the previous game, top-scored with 48 from 32 balls while Proteas international Dewald Brevis struck 41 off 29 deliveries.
The Knight Riders were on course in the run-chase when they reached 79-2 in the 10th overs but Afghanistan spinner Noor Ahmed changed the game with a match-winning spell.
Left-arm tweaker Ahmed took 3-21 in four overs as the visitors collapsed to 90-6 in 13 overs.
Ajinkya Rahane (28), Angkrish Raghuvanshi (27) and Sunil Narine (24) gave the Knight Riders the platform after four consecutive defeats but Ahmed had other ideas.
Instead it was the Super Kings that recorded their second victory in five encounters this season.
At the Sawai Mansingh Stadium in Jaipur, Rajasthan Royals produced a high-pressure chase of 221 to defeat Lucknow Super Giants, sealing a crucial result that reshaped the IPL 2026 playoff picture.
The sight of MS Dhoni walking out for Chennai Super Kings' lap of honour at Chepauk may have been the closest fans get to a farewell.
Ishan Kishan held together a nervy second innings as Sunrisers Hyderabad chased down 180 to defeat Chennai Super Kings by five wickets on Monday night.
MS Dhoni probably will not return to the Chennai Super Kings's line-up ahead of the pivotal IPL 2026 encounter against Sunrisers Hyderabad at M.A. Chidambaram Stadium in Chepauk.
