Heroics from Ambati Rayudu, who struck a 17-ball 34, helped Mumbai Indians chase down the target of 169 losing six wickets and with a ball to spare for their first ever win in Mohali in five seasons. Rayudu was also adjudged Man of the Match.
With the win, Mumbai Indians moved to the sixth spot with eight points from seven matches while Kings XI remained at the eighth place with six points from eight matches.
Opting to bat first, Kings XI Punjab got a challenging total of 168 for three in 20 overs after stand-in skipper David Hussey struck an unbeaten 68 while David Miller remained not out on 34.
While chasing, Mumbai Indians got off to a good start with James Franklin (22) and Sachin Tendulkar (34) adding 52 runs for the first wicket. Veteran Pakistani all-rounder Azhar Mahmood (2-23), who is playing as a British citizen, picked up the openers in his consecutive overs as Mumbai Indians slumped from 52 for no loss to 59 for two.
Rohit Sharma came with a brilliant 50 off 30 balls, which was studded with three fours and three sixes, to keep Mumbai Indians' chase on track.
Rohit and skipper Harbhajan Singh, who didn't trouble the scorers, were dismissed by pacer Parvinder Awana (3-39) in the 18th over which left Mumbai Indians needing to score 32 runs off the last two overs.
It looked as if Kings XI would get an easy win, but things turned in favour of Mumbai Indians in the penultimate over bowled by leggie Piyush Chawla (1-46).
Chawla was clobbered for four sixes in his last over by Robin Pietersen (16 not out) and Rayudu, both hitting two each, as 27 runs came off the 19th over and took Mumbai Indians to the threshold of a win.
Raydu and Pietsersen then held their nerves and took Mumbai Indians to a win without further loss.
Kings XI Punjab:
Nitin Saini c Patel b McKay 17
Mandeep Singh c Karthik b Singh 22
Shaun Marsh c Harbhajan b Franklin 17
David Hussey not out 68
David Miller not out 34
Extras (w 9, nb 1) 10
Total (for three wickets in 20 overs): 168
Fall of wickets: 1-35 (Mandeep, 5.2 overs), 2-46 (Saini, 7.4), 3-79 (Marsh, 12.5)
Robin Peterson 1-0-3-0
Rudra Pratap Singh 4-0-27-1
Clint McKay 4-0-36-1
Munaf Patel 4-1-41-0
Harbhajan Singh 3-0-29-0
Kieron Pollard 3-0-27-0
James Franklin 1-0-5-1
James Franklin c Saini b Azhar 22
Sachin Tendulkar c Saini b Azhar 34
Rohit Sharma c Azhar b Awana 50
Dinesh Karthik c Azhar b Chawla 3
Kieron Pollard c Mandeep b Awana 3
Ambati Rayudu not out 34
Harbhajan Singh c Marsh b Awana 0
Robin Peterson not out 16
Extras (lb 4, w 4, nb 1) 9
Total (for six wickets in 19.5 overs) 171
Fall of wickets: 1-52 (Franklin, 7.5 overs), 2-59 (Tendulkar, 9.1), 3-66 (Karthik, 10.5), 4-90 (Pollard, 13.4), 5-135 (Sharma, 17.2), 6-135 (Harbhajan, 17.4)
Praveen Kumar 4-0-25-0
Bhargav Bhatt 4-0-34-0
Parvinder Awana 4-0-39-3
Piyush Chawla 4-0-46-1
Azhar Mahmood 3.5-0-23-2
Toss: Kings XI Punjab, who chose to bat
Result: Mumbai Indians won by four wickets
Umpires: Aleem Dar (Pakistan) and Bruce Oxenford (Australia)
TV umpire: A.K.Chowdhury
Match referee: Roshan Mahanama (Sri Lanka)