After being put into bat first, Stoinis (89*) and Krunal Pandya (49 retd.) strung together an 82-run partnership to put on a decent total. Rohit Sharma (59) and Ishan Kishan (37) got MI to a flying start, but LSG bowlers kept the pressure on, as the visitors lost wickets regularly.
Mohsin Khan made a fine comeback from a long injury lay-off as the left-arm pacer defended 11 runs off the final over against the destructive Tim David to hand Lucknow Super Giants a five-run win over Mumbai Indians in the IPL in Lucknow on Tuesday. (More Cricket News) | (Scorecard)
Marcus Stoinis flaunted his raw power on his way to an unbeaten 89 off 47 balls as LSG recovered from a poor start to post 177 for three after Mumbai opted to bowl.
Mumbai were on course for a comfortable win, but fluffed the chase in the second half of the innings to end with 172 for five in 20 overs.
Mohsin, who missed the whole of the domestic season due to a shoulder injury, helped LSG take a major step towards a top-four finish by holding his nerve in the final over.
Mumbai too remain in contention for a play-off spot despite the loss.
Chasing 178 was not going to easy on this pitch, but Rohit Sharma (37 off 25) and Ishan Kishan (59 off 39) raised the possibility of a comfortable chase with a 90-run opening wicket stand off 58 balls.
Kishan looked in menacing touch while Rohit hit two sublime sixes to give a strong indication that he was back to his best.
However, both fell to leggie Ravi Bishnoi in his successive overs as the hosts were back into the game.
Going for shots from ball one was not the best option on this surface and even the usually unstoppable Suryakumar Yadav experienced that in the middle. A master at extracting runs behind the wicket, he went for his trademark scoop shot off pacer Yash Thakur, but ended up hitting it back to the stumps.
Mumbai needed 53 off the last 30 balls and with Nehal Wadhera and Tim David in the middle and Cameron Green yet to come, there was arsenal left in the tank.
However, David could not finish the game as he did against Rajasthan Royals earlier in the competition.
Earlier, Stoinis smashed eight sixes in his belligerent knock and shared an 82-run partnership with stand-in skipper Krunal Pandya (49 retired hurt) after LSG found themselves reeling at 35 for three in the seventh over.
As has been the case throughout the season, batters had a tough time on a two-paced surface.
LSG made a questionable call to leave out their leading run-getter of the season, Kyle Myers, and the move did not work. Replacing him at the top, Deepak Hooda (5) was undone by a slower ball from Jason Behrendorff
The next ball from the left-arm pacer was angled away and Prerak Mankad got a faint touch on way to the wicketkeeper while trying to run towards the third man.
The situation got worse for LSG when Quinton de Kock (16 off 15) fell in the seventh over to leave the home team reeling in the seventh over.
De Kock went for the drive off a googly from the wily Piyush Chawla but ended up getting caught behind.
The onus was on the big-hitting Stoinis and Krunal to resurrect the innings and they did that with a gritty stand before the latter got retired hurt after being seen in a bit of discomfort in the 16th over.
After that, it was all Stoinis, who began his innings with massive sixes off spinners Hrithik Shokeen and Chawla in successive overs.
Stroke-making was tough in the prevailing conditions but Stoinis used his brute force to get the much-needed boundaries and sixes.
The 18th over bowled by Jordan yielded 24 runs with the England pacer spraying it all over the place. He failed to nail his yorker and Stoinis was quick to dispatch his two balls for massive sixes down the ground besides collecting three fours off the short balls.
He finished the innings with a one-handed six off Akash Madhwal.
Mumbai leaked 54 runs in the last three overs.