Underdogs Tamil Nadu defeated much-fancied Mumbai by 15 runs in a crucial Group B match, in the inter-state Twenty20 tournament, at the Sardar Paterl Gujarat stadium in Motera, Ahmedabad, under floodlights on Monday night.

So long as Sachin Tendulkar was at the wicket, Mumbai looked heading for a thumping victory. But the moment Tamil Nadu got rid of the maestro, Mumbai presented a classic case of how to lose from a winning position.

The star-studded Mumbai team, boasting of Team India members Tendulkar, Zaheer Khan, Ajit Agarkar, Wasim Jaffer and Ramesh Powar, among others, had to score 173 runs to win the match.

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Mumbai captain Amol Muzumdar gambled and sent in Powar along with Tendulkar to open the innings. But the move backfired as Powar fell to medium-pacer P Amarnath for just 5. Jaffer also did not last long as he was consumed by fast bowler V Yomahesh when his individual score was 4.

Mumbai were 21 for 2 when the young and exuberant Rohit Sharma stepped in to accompany Tendulkar, who was already going guns.

Tendulkar and Sharma tore into the Tamil Nadu attack and put on 78 runs for the third wicket in a matter of minutes. He was enjoying every moment of his stay in the middle and hitting all the bowlers round the wicket almost at will. Even the departure of Sharma, who was bowled by R Prasanna for 25 (26 balls, 1x4, 1x6), did not make any difference to Tendulkar's mood.

But for a reprieve by Hemang Badani at short extra-cover off the bowling of Yomahesh when on 27, the Master Blaster played an explosive innings befitting Twenty20 cricket. He completed his 50, which came in just 23 balls, with a huge six off R. Ashwin. He hit another towering one off the bowling of Amarnath.

The Mumbai camp had every reason to feel that they would win with many balls to spare. So brilliantly was Tendulkar batting. However, just when he looked certain to carry the team through and also complete a deserving hundred, Amarnath bowled him neck and crop with a ball that kept very low.

Tendulkar's 68 runs came off 32 balls. The 10 fours and two sixes that he smashed showed the disdain with which he treated the Tamil Nadu bowlers.

Mumbai were 118 for 5 when Tendulkar left. Surprisingly, the rest of batsmen caved in against some really intelligent and economical bowling by the Tamil Nadu spinners, particularly C Ganapathy.

Muzumdar scored 1, Vinit Indulkar 12, Agarkar 1 and Zaheer 3.

Wicketkeper Vinayak Samant and Nilesh Kulkarni were not out on 9 and 21 respectively as Mumbai posted 157 for 8 in 20 overs.

Ganpathy was the wrecker-in-chief with amazingly economical figures of 4-1-15-3. He bowled a maiden over to Zaheer Khan, something rare in this type of cricket. Prasanna was also economical as he gave away only 13 runs in his two overs while taking a wicket.

Earlier, batting first after losing the toss, Tamil Nadu scored 172 for 5 in 20 overs. Opener S Anirudha, who failed against Bengal on Sunday, made amends with a sparkling 49 off 39 balls and hit six fours.

His partner V Devendran also batted well and scored a breezy 30 (20balls, 6x4). The two put on 51 for the first wicket and gave a sound start to their team.

While Hemang Badani scored 23 off 19 balls, inclusive of a four and six, Dinesh Kaarthick scored 26 off 14 deliveries. He hit three fours and a six.

S. Vidut also contriubted a quickfire 28 (22 balls, 2x4).

No Mumbai bowler could make an impression on the Tamil Nadu batsmen, including Zaheer Khan, who was hit for 34 runs in his four overs, and Agarkar, who gave away 21 in his 2 overs.

In Tuesday's matches at Motera, Mumbai takes on Haryana in the morning while Bengal plays Madhya Pradesh in the evening.