Mumbai Indians on Tuesday left behind on-field disappointments and off-field controversies to pull off their maiden win with an emphatic seven-wicket decimation of Kolkata Knight Riders in an Indian Premier League outing in Kolkata.After restricting Knight Riders to a modest 137 for 8, the visitors overcame early jolts to coast to a comprehensive victory with eight balls to spare to bag their first two points after losing four matches at a stretch.Dwayne Bravo (64 not out; 52 balls, 8x4, 1x6) and Robin Uthappa (37 not out, 37 balls, 5x4) took the game away from the Knight Riders with a 113-run unfinished fourth wicket stand as the Mumbai Indians reached 138 for 3 in 18.4 overs to hand the hosts their second defeat in four matches.West Indian Bravo went all guns blazing, while Uthappa played an uncharacteristic second fiddle at the other end, as the Knight Riders bowlers could do nothing to unsettle the duo on a sporting pitch, which was a far cry from the two-paced dry track that had been widely criticised nine days back.With their regular captain Sachin Tendulkar still out of action owing to a groin injury, and stand-in skipper Harbhajan Singh banned from the IPL for slapping Kings XI Punjab player S Sreesanth, the Mumbai side played their hearts out to dazzle the 80,000-strong crowd at the Eden with an all-round show.Set an asking rate of 6.9 per over, the visitors got off to a disastrous start, as Ajit Agarkar got rid of opener Ajinkya Rahane (4) in the first over.