Spurs came from a goal down to win the Europa League Group J encounter 3-1 at White Hart Lane.
Richard Almeida put Qarabag in the lead from the penalty spot after seven minutes, but Son Heung-min restored parity in the 28th minute.
Son made it 2-1 to Tottenham just two minutes later, and Argentina international attacker Erik Lamela wrapped up the scoring in the 86th minute.
Alli started the game and played for the entire 90 minutes, and he was delighted with Spurs’ performance in their opening match of the 2015-16 Europa League campaign.
“It was a solid performance from us,” the 19-year-old told BBC Sport. “We were unfortunate to give away the first goal but it was a good overall display.
"They made us work for the win - they're not a bad side. They did well. I'm happy for Son that he got two goals and that I played a part. It's always good to help the team.”
Tottenham goalkeeper Hugo Lloris added: "The most important thing is to get the three points, it was the target before the game and we did well after conceding the penalty.
"We started the game too slowly and after conceding, we picked up our level and came back into the game."
Tottenham did not play well in the opening minutes, but as the game wore on, they looked comfortable and deserved the three points.
The North London outfit now need to build on this victory and try to win the group.
Spurs need to take the Europa League seriously, as winning it will give them a chance to feature in the 2016-17 Champions League campaign.