After being put in to bat, KXIP got off to a good start with openers Virender Sehwag and Murali Vijay combining to score 60 runs in 6.4 overs.
Sehwag was striking the ball well and raced to 36 off 19 balls with the help of six fours and a six, before his innings was cut short by Harbhajan Singh.
After the blistering start by KXIP, MI pulled things back thanks largely to a fantastic bowling effort from Harbhajan Singh, who first removed Sehwag then went on to scalp Murali Vijay. He finished with impressive figures of 4-0-20-2.
However, the most sought after wicket of the match was taken by debutant spinner Jagadeesha Suchith as he removed the dangerous Glenn Maxwell cheaply for six runs.
KXIP skipper George Bailey and David Miller (24) then steadied the innings, but the big-hitting Miller was scalped by Lasith Malinga in the 16th over.
Bailey scored his first half-century in IPL helping his team go past the 150-run mark as KXIP scored 177 for 5 in their 20 overs.
Chasing the stiff target, Mumbai Indians got off the the worst start possible as they lost skipper Rohit Sharma to Sandeep Sharma in the first over.
MI lost wickets in heap early on and when Mitchell Johnson removed Ambati Rayudu for 13, the home team found themselves tottering at 46 for 5.
MI slipped further in the chase when Akshar Patel sent back the big-hitting duo of Corey Anderson (5) and Kieron Pollard (20).
Along with Harbhajan, Suchith (34*) combined for a 100-run stand for the seventh wicket, but the blitz came a bit late as KXIP won the tie by 18 runs.
However, Harbhajan Singh provided ample entertain for the Wankhede crowd hitting 64 off 24 balls and more importantly, reduced the margin of defeat.