In a must-win match to make the main round, Odisha were set a modest 122 run target after Bengal elected to bat but their batters put up a freak display and lost wickets at regular intervals to be restricted to 112 for nine.
With an all-win record from four matches, Bengal (16 points) qualified to the main round as toppers along with group runners-up Jharkhand (8).
Rookie left-handed opener Vivek Singh (38 from 27 balls; 3x4, 2x6) was Bengal's top scorer, while Arnab Nandi was instrumental in the win with an allround effort.
Bengal were in danger of being bowled out losing two wickets in the 17th over to be 98/7 but Nandi held his nerve and remained unbeaten on 29 (25 balls; 3x4) to push the total to 121/7.
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Required to score at run-a-ball, Odisha batsmen never showed any appetite after their inform opener Paresh Patel (17) was bowled by Sanjib Sanyal in the fourth over.
Meanwhile, Bengal received a setback when their main pacer Ashok Dinda injured his left hand while fielding and did not turn up on the field again with his hand in a sling.
Dinda went for an MRI even as skipper Lahiri said it appeared to be a "minor injury".
Bengal will be missing their top stars skipper Shukla, Manoj Tiwary, Wriddhiman Saha, Ashok Dinda and Veer Pratap Singh in the main round of the tournament since they will be leaving for their respective franchises' preparatory camps for the upcoming IPL-7.
Brief Scores:
Bengal 121/7; 20 overs (Vivek Singh 38, Arnab Nandi 29 not out, Manoj Tiwary 22; Biplab Samantray 2/18, Jayant Behera 2/23) b Odisha 112/9; 20 overs (Govind Podder 39; Arnab Nandi 2/7, Sanjib Sanyal 2/14, Pritam Chakraborty 2/26, Aamir Gani 2/26) by nine runs.