Batting first, Bengal scored 293/9 riding on opener Abhimanyu Easwaran's 103 and an unbeaten 80 from skipper Manoj Tiwary.
Easwaran's innings was laced with 12 boundaries in 114 balls while Tiwary hit four boundaries and two sixes in 76 deliveries.
Bengal lost six wickets for 51 runs from a relatively comfortable 242 for 3 as they failed to cross the 300-run mark.
However Maharashtra made a short work of the chase as Tripathi hit 12 boundaries and four sixes in his 125 off 102 balls as Maharashtra reached the target in 46th over.
The duo put on 65 runs in 13.3 overs before Tripathi took charge of the chase and sealed the issue in an unbroken 107- run partnership with Ankit Bawne (22).
Brief Scores: At Nadaun: Bengal 293/9; 50 overs (Abhimanyu Easwaran 103, Manoj Tiwary 80 not out; Anupam Sanklecha 2/39, Shrikant Mundhe 2/84) lost to Maharashtra 294/3; 45.5 overs (Rahul Tripathi 125 not out, Ruturaj Gaikwad 77) by seven wickets.