Chasing 121 for victory, Punjab got off to a good start as they posted 43 runs in the first six overs, to ease pressure off themselves as they needed just 56 runs off the last 10 overs.
The win has kept Punjab's play-off hopes alive. They have one more game to play. Punjab are fifth with 16 points. Chennai finished their league engagements with 17 points. MS Dhoni-led side, currently fourth after this game, will rely on other results to take them to the semi-finals.
Gilchrist was at his best, made his presence felt as he took four catches during Chennai's innings and scored a magnificent 64 not out off 46 balls to script another win for Punjab against Chennai, to finish a double in IPL 5. Gilchrist's innings included nine boundaries and two sixes.
Though David Hussey (9), Nitin Saini (1) and Siddharth Chitnis (11) all got out cheaply. Mandeep Singh and Gilchrist had earlier given Punjab a decent start, as they added 51 runs for the first wicket.
Ben Hilfenhaus tried his best to restrict Punjab, as he conceded only 20 runs off his 4 overs, and grabbed the wicket of Chitnis.
It was an easy chase, as Gilchrist shone with the bat. With 7 runs needed off 5 overs, Azhar Mahmood hit the winning runs, a boundary, and sealed the win in Punjab's favour in the 17th over, with 21 balls to spare.
Chennai Super Kings' Innings Report: Chennai Super Kings, playing a must-win game to stay afloat in the tournament managed just 120/7 in their 20 overs as Parvinder Awana and Praveen Kumar bowled extremely well for Punjab to restrict Chennai to a modest total at HPCA stadium in Dharamsala on Thursday.
With the strip assisting pacers, Praveen Kumar and Parvinder Awana left Chennai batsmen tumble, as they struggled to score runs. Praveen started off very well, as he conceded only 18 runs off his 4 overs and claimed two wickets, by removing openers within the first five overs.
Awana, back from his match-winning spell against Delhi Daredevils, put up a great show as he conceded just 12 runs off his 4 overs and picked up two crucial wickets of MS Dhoni and Ravindra Jadeja.
Chennai got off to a poor start, as Murali Vijay (10) and Michael Hussey (7) were dismissed within 5 overs, and the team struggled to put runs on the board, as they added just 25 runs off their mandatory powerplay.
MS Dhoni, also failed to accelerate the run-rate, as he fell in the 11th over, while Suresh Raina (17) too did not create an impact as he gifted a wicket to Azhar Mahmood after hitting a six and a four off his over.
Albie Morkel (14) and Ravindra Jadeja (13) too failed to contribute in Chennai's crucial tie, as Azhar Mahmood and Awana picked their wickets respectively.
Chennai scored at a snail's pace, as they reached 100 in 17.5 overs, as they added just over 7 runs per over in their last ten. Dwayne Bravo top scored for Chennai with 48 off 43 balls, which included three sixes and 2 boundaries.
With a target of 121, Kings XI need good partnerships at the start of the innings, while Chennai need early wickets.
Chennai Super Kings: MS Dhoni (captain and wicketkeeper), Murali Vijay, Srikkanth Anirudha, Michael Hussey, Ravindra Jadeja, Suresh Raina, Dwayne Bravo, Ben Hilfenhaus, Ravichandran Ashwin, Albie Morkel, Yo Mahesh
Kings XI Punjab: Adam Gilchrist (captain and wicketkeeper), David Hussey, Gurkeerat Singh, Siddarth Chitnis, Parvinder Awana, Azhar Mahmood, Nitin Saini, Piyush Chawla, Mandeep Singh, Praveen Kumar, Ryan Harris
Umpires: Vineet Kulkarni (India) and Shahvir Tarapore (India)
Third umpire: Billy Bowden (New Zealand)
Match referee: Ranjan Madugalle (Sri Lanka)