Karnataka stunned heavyweights Mumbai by nine runs despite Test vice-captain Ajinkya Rahane's 75 off 54 balls in a Syed Mushtaq Ali Trophy group B match on Thursday.
Leg-spinner KC Cariappa turned it around with two wickets in two balls to end with fine figures of 3/26, while off-spinner Krishnappa Gowtham also contributed immensely with his 2/26 as Karnataka restricted Mumbai to 157/6, defending 167.
Opting to bowl, Mumbai skipper Rahane led their challenging chase with a fine half-century but the mystery spinner Cariappa removed the star Indian batsman and cleaned up another international Shivam Dube (3) with his very next ball to put brakes on their chase.
Gowtham then triggered another collapse when he dismissed Siddhesh Lad (32) to break his 88-run partnership with Rahane.
Rahane steered the show after his dangerous opening partner Prithvi Shaw (4) fell cheaply, while talented Yashasvi Jaiswal (13) became Gowtham's first victim after the Powerplay.
Rahane's 54-ball knock was studded with six fours and three sixes as Mumbai were cruising with 125 for 2 in the 16th over before all hell broke loose.
Cariappa's magical bowling at the death meant Mumbai needed 24 runs off the final over with four wickets in hand as seamer Prasidh Krishna ensured that they fell short by nine runs.
Earlier Manish Pandey (84 from 64 balls; 7x4, 2x6) and Karun Nair (72 from 53 balls; 6x4, 2x6) put on a 149-run partnership to power Karnataka to a challenging 166/4.
Put on, Karnataka had a jittery start with debutant Mumbai seamer Mohit Avasthi taking two wickets in his first two overs en route to his 2/32.
India's back-up Test opener Mayank Agarwal was out for a golden duck, while the talented youngster Devdutt Padikkal (5) followed suit in the third over before Pandey and Nair took charge and stayed till the final over.
In the first match at the venue, a new look Bengal team began its campaign by thrashing Chhattisgarh by seven wickets.
Brief Scores
Chhattisgarh 118/7; 20 overs (Akhil Herwadkar 73; Mukesh Kumar 2/26) lost to Bengal 119/3; 17 overs (Sudip Chatterjee 51 not out, Wriddhiman Saha 24; Ravi Kiran 2/24) by seven wickets.
Baroda 124/9; 20 overs (Bhanu Pania 55; Nitin Yadav 3/22) lost to Services 128/8; 20 overs (Diwesh Pathania 41 not out; Ninad Rathva 3/8, Krunal Pandya 2/12) by two wickets.
Karnataka 166/4; 20 oves (Manish Pandey 84, Karun Nair 72; Mohit Avasthi 2/32, Tushar Deshpande 2/38) b Mumbai 157/6; 20 overs (Ajinkya Rahane 75; KC Cariappa 3/26, Krishnappa Gowtham 2/26) by nine runs.