Allen smashed 93 off 35 balls - including four fours and 10 sixes - as Kolkata posted a mammoth target of 248 for the opposition. Gujarat only mustered 218-4 in 20 overs in reply.
The New Zealand batter had managed just 81 runs in his first five matches and was dropped for three games before returning to score an unbeaten 100 off 47 balls in his second innings back earlier this month.
“To be honest, at the start of the tournament, I was putting far too much pressure on myself to perform, and I was probably a shell of a human for a bit there and it was all self-inflicted," Allen told reporters in Kolkata.
"I love playing cricket, I love batting, and I wasn’t enjoying it as much as I should have at the time because I was putting too much pressure on myself.
"So having those few games off, really did me a good thing."
Allen said a simpler approach and renewed focus on enjoying his cricket had been key to his resurgence in the unpredictable 20-overs format.
“I think what I really worked on was if I am relaxed and I am enjoying myself and I watch the ball harder, I am in a better position, and I am a better cricketer for it," Allen said.
"So I think the main thing was to keep enjoying what I was doing, keep learning, and pressure is something that I put on myself. We are very blessed to be doing what we do, so the pressure was all me."
Kolkata, seventh with 11 points, remain in a tight race for the top four with two games in hand. They next face already-eliminated Mumbai Indians on Wednesday.