Inserted in on a seaming, pacy and bouncy Wankhede Stadium track by Mumbai skipper Nilesh Kulkarni, the Bengal batsmen never full recovered from a shaky start of 2 for two before being dismissed at the stroke of tea.
Hazare grabbed 5 for 36 in twenty overs, including the first three wickets to fall, and was well supported by fellow medium-pacers Usman Malvi and Avishkar Salvi who claimed three and two wickets respectively.
Sourasish Lahiri, who batted at one down for Bengal, top-scored with a stubborn 49. But his dismissal at 107 just before lunch after a stay of 107 minutes, during which he faced 74 balls and struck 8 fours and a six, triggered a collapse as Bengal lost their last eight wickets for 64 runs.
Lahiri, who added 78 runs with Devang Gandhi (30 in 143 minutes and off 90 balls) was fifth out, bowled by Hazare who had earlier sent back the two Bengal opening batsmen Arindam Das and Shubomay Das cheaply with away swinging deliveries.
Bengal, for whom Laxmi Ratan Shukla made a breezy 27 before he was bowled by Malvi when he shuffled too far to his right, fought back well when burly pacer Shib Shankar Pau sent back Mumbai openers Sahil Kukreja and Wasim Jaffer with only 13 on board.
Mumbai, then, recovered to 50 for two before bad light ended play with 3.5 overs remaining. Vinit Indulkar (17) and Amol Muzumdar (23) were the not out batsmen at close.