Put into bat, the home team posted a challenging total of 183/8 with the help of two fantastic knocks from Azhar Mahmood (80) and Shaun Marsh (63). In reply, the Indians could only manage 133 in 19.1 overs with none of the batsmen playing an anchor's knock.
With this win, the Punjab-based team finished their IPL campaign sixth with 16 points, thus not qualifying for the playoffs.
Kings XI lost Gilchrist (5) and Mandeep Singh (1) cheaply by the third over which put the hosts in a spot of bother but Mahmood and Marsh struck a 148-run third wicket partnership which set up their innings.
The former Pakistani all-rounder hit eight boundaries and four sixes in his 44-ball knock while Australia's Marsh scored 11 boundaries all around the scenic ground, located in the middle of the snow-covered peaks.
The lower order failed to capitalise on the partnership in the last few overs which is why they could not reach 200. But Manan Vohra played an important 8-ball 20-run cameo which included three boundaries and one huge six propelling the Punjab-based team to a par-180 score.
Sri Lankan Lasith Malinga was the pick of the bowlers picking up three wickets from his four overs but also went for 39 runs at 9.75 runs per over. Mumbai, having already qualified for the playoffs, rested lead pacer Mitchell Johnson, who gave way way to Nathan Coulter-Nile, who made his IPL debut.
In reply and with the absence of Sachin Tendulkar, the Mumbai Indian batsmen could not strike a long-enough partnership and kept losing wickets at regular intervals to hand the game to Kings XI. Tendulkar, who missed the last match too, is currently nursing a hand injury.
Aditya Tare (22), Ambati Rayudu (26), Rohit Sharma (25) and Kieron Pollard (22) got starts but could not convert them into much-needed big-scores to overcome the Punjab total.
Mumbai were nine wickets down when Dhawal Kulkarni, who got injured while bowling, did not come out to match and was stated to be absent hurt, giving the match to Punjab.
In a surprise, Kings XI skipper Gilchrist, already knowing that they had won the match decided to bowl the last over and picked up a wicket on the first ball that of Harbhajan Singh (5), who was caught at long-on.
Praveen Kumar, though took only wicket, was among the best bowlers by bowling a tight line and not allowing the Indians to score heavily off him.
Mahmood also shone with ball taking 2/24 in his quota of four overs. Sandeep Sharma and Piyush Chawla also took two wickets each while Parvinder Awana clinched one.