Fabregas struggled for playing time early last season, Conte's first at the club, before fighting his way in as Chelsea went on to win the Premier League title.
The Spain international has already made 12 league starts this season – he made 13 in 2016-17 – and Conte hailed the 30-year-old.
"Cesc at the start of last season didn't play a lot, but I was very happy because through the work he tried to change my mind and it happened," the Italian said ahead of his side's Champions League clash against Atletico Madrid.
"If you remember the second part of last season he started to play with regularity and first part of last season I played almost every game with [N'Golo] Kante and [Nemanja] Matic.
"But in the second part of the season Cesc played a lot of games, and he was very important for us to win the title.
"This season he has continued to work very hard, showed me great commitment and behaviour and the coach has to make the best decision."
Fabregas has won two league titles since joining Chelsea from Barcelona in June 2014.
Conte believes there is more to come from Fabregas, who has contributed a goal and three assists in the league this season.
"He is still young for sure. When you are 30 years old you have at least five more years to play football," he said.
"At this level you must have great desire and great will to play at this level because it is not simple.
"There is a lot of competition with other players but Cesc has great ambition. He's a winner in his mind, in his mentality. For this reason he is very strong."