Du Plessis' 86 off 59 balls guided Chennai to 192-3, a total their bowlers defended by restricting Kolkata to 165-9
Faf du Plessis smashed an attacking half-century to help Chennai Super Kings thrash Kolkata Knight Riders by 27 runs and clinch their fourth Indian Premier League title on Friday.
Du Plessis' 86 off 59 balls guided Chennai to 192-3, a total their bowlers defended by restricting Kolkata to 165-9 in the final in Dubai.
Opener Venkatesh Iyer smashed a 32-ball 50 but the knock was not enough to stop Chennai's MS Dhoni from a landmark win in his 300th match as T20 skipper.
Shardul Thakur took three wickets including twin strikes in one over to hurt two-time champions Kolkata who came into the final on the back of four successive wins.
Spinner Ravindra Jadeja and pace bowler Josh Hazlewood took two wickets each.
Eoin Morgan's Kolkata won the toss and elected to field but their bowlers failed to get a wicket until the ninth over and took a hammering in Dubai.
Ruturaj Gaikwad fell for 32 off-spinner Sunil Narine but Du Plessis kept up the charge to raise his fifty with a six amid raucous support for Chennai at a nearly packed stadium.
The South African veteran smashed seven fours and three sixes and put on key partnerships with Robin Uthappa, who made 31, and Moeen Ali, who hit an unbeaten 37 off 20 balls.
Du Plessis was out on the final ball off pace bowler Shivam Mavi. Narine was two-time champions Kolkata´s best bowler with figures of 2-26.
Kolkata started strongly with Iyer and Shubman Gill, who made 51, putting on a quickfire opening stand of 91.
But Chennai hit back with Thakur's twin strikes in one over including Iyer's key wicket as wheels came off the Kolkata chase.
Chennai, winners in 2010, 2011 and 2018, remain one of the most successful IPL franchises after five-time champions Mumbai Indians who failed to defend their title this season.