Bangalore, Mar 24 (IANS): In a battle of wits and nerves, Royal Challengers Bangalore (RCB) uncrowned Chennai Super Kings (CSK) late Tuesday, by winning their fourth game on trot by 36 runs in the IPL-3 T20 at the Chinnaswamy cricket stadium here.

With six mighty sixes and three fours, local lad Robin Uthappa scored an unbeaten 68 in 38 balls to give a shaky Challengers a defendable score of 171 for 5 wickets in 20 overs during the first half.

But it was the medium pacer Vinay Kumar who wrecked Super Kings with a superb spell, taking four wickets for 40 runs in four overs and restricting them to 135 for 7 wickets in 20 overs.

Riding high on its winning spree after losing their first game to Kolkota Knight Riders March 14, Challengers were put to bat after its skipper Anil Kumble lost the toss to Super Kings stand-in captain Suresh Raina on a dry but placid wicket.

Though Super Kings succeeded in restricting Challengers to 171 with tactical bowling and intelligent fielding, their opening batsman Mathew Hayden failed to deliver this time with his powerful mongoose bat.

Having lost wicket-keeper Parthiv Patel in the first over to medium pacer Praveen Kumar for 2, Super Kings struggled to keep the score ticking in the first six overs, as the veteran Kumble shuffled bowlers and unleashed speedster Dale Styn.

Just as Hayden began to open-up with a flurry of fours in Kallis first over, a brilliant throw by Rahul Dravid at the non-striker's end sent the Aussie legend packing.

Hayden remained top scorer of Super Kings with 32 runs, including five fours in 28 balls, followed by S. Badrinath 31 in 17 balls and G. Bailey 19 in 27 balls.

A huge sixer by Raina in the first over raised hopes of Super Kings being in the game but it was not to be when he exited soon with a simple catch near the fence to Kallis of Vinay.

A rear-guard action by middle order Badrinath and Albie Morkel that helped Super Kings to cross the 100-mark failed to sustain the momentum even as Kumble kept the pressure on by bringing Styn and Kallis back into the attack.

A final onslaught by Morkel and R. Ashwin could take Super Kings past 135 in the final over when the former was bowled over by Vinay.

Earlier, confident and upbeat Challengers made a caution start and found the going tough in the first six overs itself, thanks to tight bowling and close fielding of Super Kings.

Kallis, who remained unbeaten in the previous four games and took RCB to the winning post in the last three matches, was unlucky to get out to an inside edge, with Muralitharan's ball knocking off the bails before speeding away to the fence.

Dravid, who took time to settle, was also bowled out by Muralitharan for 14, including two to the fence in 11 balls.

Opener Manish Pandey, who played a steady innings to score 20 in 28 balls with two fours, did not last long as he hit a skier and was caught brilliantly by Raina.

Uthappa, who walked in after Dravid's exit, breathed some life into the game that was meandering by building two belated partnerships with Virat Kholi first and wicket-keeper Mark Boucher and ensured Challengers had a respectable score on the board to give a run for Super Kings in the later half of the match.

Uthappa was declared man of the match though many expected Vinay to get or share it.