Raina played a mercurial 38-ball knock as he smacked five huge sixes and three boundaries and also added rapid 30 runs with skipper MS Dhoni (14 not out) in final three overs.
Dhoni hit two boundaries in his 9-ball innings.
Shakib Al Hasan dismissed Raina with the final ball but it turned out to be too little too late.
Chennai lost Michael Hussey (54) soon after Raina slammed 27-ball fifty to lead their innings against Kolkata.
Birthday boy Hussey smashed two huge sixes and four fours and raced to fifty in just 38 balls. Hussey also added 73-run second wicket stand with mercurial Raina.
Electing to bat, Chennai lost Murali Vijay (42) after he added a quick 87-run opening stand with Hussey.
Centurion in last match, Vijay played another aggressive innings as he scored 42 off 32 balls which included a six and four boundaries before Rajat Bhatia got better of him in the eleventh over.
Bhatia gave Kolkata the crucial breakthrough and reduced Chennai to 87/1 in 10.2 overs.
Chennai openers changed gear after a cautious start as they took Chennai to 50 runs without any loss in just 5.5 overs.
Earlier, Chennai skipper Mahendra Singh Dhoni won the toss and decided to bat against Kolkata.
“Pitch has a bit more grass roots into it, depends on how much they have rolled it, I don’t think it should spin much. We were quite consistent during the league stage, we won one and lost one,” MS Dhoni said after winning the toss.
Chennai are playing the same eleven, which crushed Delhi Daredevils in the Qualifier 2, for the match.
Chennai Super Kings: Mahendra Singh Dhoni (capt/wk), Michael Hussey, Murali Vijay, Suresh Raina, Ravindra Jadeja, Dwayne Bravo, Albie Morkel, Ravichandran Ashwin, Ben Hilfenhaus, Shadab Jakati, Subramaniam Badrinath.
Kolkata Knight Riders: Gautam Gambhir (capt), Jacques Kallis, Yusuf Pathan, Manoj Tiwary, Laxmi Ratan Shukla, Rajat Bhatia, Sunil Narine, Brett Lee, Iqbal Abdulla, Manvinder Bisla (wk), Shakib Al Hasan.