Earlier, Matthew Short top-scored for PBKS with a 24-ball 36.
Towards the end, Sam Curran (22) and M Shahrukh Khan (22) played some big shots to take PBKS past the 150-run mark.
For GT, debutant Mohit Sharma (2/18), Rashid Khan (1/26), Alzarri Joseph (1/32), Mohammed Shami (1/44) and Josh Little (1/31) picked up the wickets.
Besides Gill, Wriddhiman Saha made a 19-ball 30 for GT.
Brief scores:
Punjab Kings: 153 for 8 in 20 overs (Matthew Short 36; Mohit Sharma 2/18).
Gujarat Titans: 154 for 4 in 19.5 overs (Shubman Gill 67, Wriddhiman Saha 30; Harpreet Brar 1/20).