Chasing a target of 162, Royal Bengal Tigers were put on the victory path by their openers Hamish Marshall and Deep Dasgupta.
The opening pair was associated in a 132-run partnership before Dasgupta was ruled leg before wicket to Shabbir Ahmed.
Dasgupta faced 46 balls for his knock of 54 which contained four fours and two huge sixes. Craig McMillan joined Marshall and they surpassed Chennai Superstars' total by scoring 162 for 1 with five balls to spare. Marshall remained not out on 80 which came off 54 deliveries. He hit eight boundaries and three sixes.
McMillan's unbeaten knock of 21 contained four fours.
Earlier, A 90-run partnership between Hemant Kumar Badani and R Sathish helped Chennai Superstars post 161 all out in 19.5 overs.
Chennai Superstars captain Stuart Law won the toss and elected to bat. Ganapathi Vignesh and Hemant opened their innings. Andre Adams struck early scalping Kumar in the second over with 12 runs on the board.
Adams cut short Vignesh's cameo of 22 runs in the fourth over. At the end of the 5th over Chennai Superstars were placed at 30 for 2. The big wicket of Russel Arnold followed by run out of Jesuraj (0). Superstars were struggling at 59 for 4 in the ninth over.
ICL Point Table
Rajagopal Sathish got into the act right away taking 22 runs off Upul Chandana's 13th over. Sathish in company of Badani was working up a fine partnership for the 5th wicket and a couple of productive overs in the crucial middle innings' stage, had the Chennai side gain back the momentum at 119 for 4 at the end of the 15th over.
Badani brought his third ICL fifty off 40 balls in the 18th over.
Sathish followed suit brining his half century off only 25 balls a ball later.
The brilliant 90- run partnership for the fifth wicket was finally ended by the impressive Eklak Ahmid, scalping Sathish for a well made 50 laced with 5 fours and 3 sixes. Just when Chennai were trying to run away to a mammoth total Upul Chandana struck in the penultimate over with three wickets for only a single run.
Chandana finally ended his spell with brilliant figures of 4 for 38. The eventful first saw Chennai Superstars set the Royal Bengal Tigers a competitive target of 162. For the Royal Bengal Tigers Chandana (4 for 38) and Eklak Ahmid (3 for 21) were the most successful bowlers.
It was Tigers' fifth win from seven encounters. With ten points they are now tied with Superstars who also have the same number of points (five wins, two defeats). Both have brightened their chances to qualify for semi-finals.
Marshall was declared man of the match.
Brief scores: Chennai Superstars: 161 all out in 19.5 overs (Ganapathi Vignesh 22, Arnold 21, Hemant Badani 55, Rajagopal Sathish 50, Chandana 4 for 38, Ahmid 3 for 21, Adam 2 for 21).
Bengal Royal Tigers: 162 for 1 in 19.1 overs (Hamish Marshall 80 not out, Deep Dasgupta 54, Craig McMillan not out 21, Shabbir Ahmed 1 for 33).