Rohit, who made 84 not out when the teams met in the first leg clash at Kolkata, continued to be the thorn in KKR's flesh while Pollard took the game away with his whirlwind knock that contained six huge hits over the fence and two fours.
Rohit put on 72 runs in 30 balls for the unbroken fifth wicket with Pollard, who belted three sixes each in two overs as MI chased down the competitive score of 174 for five with two overs to spare.
It was MI's 13th win in 18 head-to-head clashes against KKR and their fourth victory this season in eight appearances that boosted their points tally to eight.
This was also two-time title-winners KKR's second loss, both to MI, in six matches this season.
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MI lost opener Parthiv Patel in the second over, caught behind by Yusuf Pathan off Jaydev Unadkat, but their two best batsmen of the season - captain Rohit and one-down Rayudu - not only repaired the innings but also gave it the early momentum.
Rohit struck two fours on the off-side off Yadav before smashing Unadkat over square leg for a six.
Rayudu followed suit by pulling the left-arm pacer for three fours, including two identical steers to the third man fence, and the bowler gave away 19 runs in the sixth over at the end of which MI were ahead of the required run-rate with 64 on the board.