Offspinner and Mumbai captain Harbhajan Singh found his rhythm when it mattered as he dismissed in-form batsmen Chris Gayle for 5 and Virat Kohli for 11 to turn the match around after Bangalore had appeared in control at 65-2 after 10 overs, needing another 75 for victory from 60 balls.
Man-of-the-match Harbhajan finished with 3-20 as he led a fine bowling performance to bowl out Bangalore for 108 in 19.2 overs after New Zealander James Franklin top-scored with 41 to help Mumbai post 139 off 20 overs.
"We have performed outstandingly," Harbhajan said. "We were right in the game when we went in to bowl. It was just a matter of getting Gayle, Dilshan and Kohli, fantastic effort by the boys."
Mumbai needed special permission from organizers to field five foreign players in the tournament after injury ruled India internationals Sachin Tendulkar, Munaf Patel and Rohit Sharma out.
"If without Sachin, Rohit and Munaf we can achieve so much, we can achieve greater heights when they come back," Harbhajan said.
Opener Tillakaratne Dilshan hit a breezy 27 with five boundaries to give IPL runner-up Bangalore a flying start before fast bowler Lasith Malinga, who was later named man of the series, yorked him to give Mumbai a vital breakthrough with the first of his two wickets.
However, with Gayle, who scored 92 in the semifinal, and Kohli, in hot form following two back-to-back fifties, in the middle it was important for Mumbai to strike quickly to make an impact.
Harbhajan did just that, as he struck in his first over to dismiss Gayle lbw. After young leg-spinner Yuzvendra Chahal dismissed Mayank Agarwal for 14, Harbhajan had Kohli caught at deep midwicket by Aiden Blizzard.
Pacer Abu Nechim, Yuzvendra Chahal and Malinga kept a tight line and chipped away at Bangalore.
Medium pacer Raju Bhatkal took 3-21 and New Zealand spinner Daniel Vettori chipped in with 2-30 as Mumbai, which had three run-outs, struggled to put up a decent score before Franklin lifted the innings with a fine knock.
"We thought it was tough but gettable. We got a good start but things went pear-shaped after that," Bangalore skipper Vettori said.
