After notching up 468 in their first innings, Punjab pacer Manpreet Goni's four wickets rattled the Mumbai batting line-up as they were all out in 60.3 overs at the Saurashtra Cricket Association Stadium.
In their second innings, Mumbai were 94 for two at stumps on the third day, still trailing by 189 runs.
It may yet not be enough for Punjab, unless of course Tamil Nadu, having taken a lead, lose outright to Gujarat.
It took a 101-run sixth-wicket stand between Sufiyan Shaikh (67) and medium-pacer Shardul Thakur (70) to rescue Mumbai from 37 for five.
Mumbai's resistance didn't last too long after this partnership.
In the second innings, Mumbai rode on a 72-run stand between Shreyas Iyer and Armaan Jaffer for the second wicket. At close of play, Shreyas was unbeaten on 59, alongside nightwatchman Vishal Dabholkar (2).