The home side were down by a first half goal scored by the visiting team's impressive mid-fielder Eugeneson Lyngdoh in the 30th minute.
But they fought back with vigour in a fast-paced second half to notch the equaliser through Brazilian import Josimar Da Silva in the 49th minute to earn a draw.
It was the third successive drawn encounter between these two sides in the tournament's history following two stalemates last year when Bengaluru made their debut and went all the way to the title.
Bengaluru did all the running in the first half and impressed with their short-passing game at good speed to run the Mumbai defence ragged and deservedly took the lead.
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The initial chance came Mumbai's way when in the 12th minute Josimar fed Ashutosh Mehta well inside the box only for the latter to be foiled in the nick of time by Bengaluru FC custodian L Ralte.
But, the home team fell behind 13 minutes later when defender John Johnson essayed a long ball for Rooney to pass it on for Lyngdoh to score with a top of the box left-footed effort that beat Lal.