Brathwaite's explosive innings of 43 runs off 29 balls included 4 sixes and ensured Sunrisers posted a respectable score of 7/139 from their 20 overs.
However, it proved not to be enough, with Chennai chasing down the total with five balls to spare.
After finishing top of the IPL table after the regular season, Brathwaite's Sunrisers will get a second opportunity to qualify for the final when they take on the winner of tonight's match between the Kolkata Knight Riders and Rajasthan Royals.