Cahill came off the bench in the 88th minute on Sunday in his probable farewell to the Stamford Bridge faithful, playing the final moments of his team's 3-0 defeat of Watford.
It was his eighth appearance in all competitions during a frustrating 2018-19 season which has seen him relegated to the sidelines, while in the Premier League he has managed just two cameos off the bench.
As he prepares for his next challenge, the 33-year-old cut loose prior to the game with heavy criticism of Sarri.
"If you are not playing a player, any player, for two, three, four games, then you don't have to give a reason for that. But if it gets to eight or nine games, then you have to explain the situation. What's going on? But the manager hasn't done that," Cahill told the Telegraph in an interview published hours before Sunday's kick-off.
"I see some of the situations with players who won the title with Chelsea, not just myself, and it just hasn't been right. It makes it very hard for me to have respect for someone who has not respected what some of us have won with the club."
Those harsh words did not provoke Sarri into denying his unhappy charge the chance to say farewell to Chelsea's fans on Sunday, and after the game he insisted that there were no problems between the defender and himself.
“I don't know the situation, I'm sorry. It's not important for me. Cahill, during the season, was really very professional," the Italian explained to reporters.
"He played only five, six or seven matches, but he was really very important in the training ground, in the dressing room.
"Today was his last match for Chelsea, so it was important for him to be on the pitch, only for a few minutes but I still think it was really very important for the fans and for him.
"Here, Gary won everything. And so I think he had to say goodbye to the stadium, to the fans, to the club.”
All three London clubs will have the chance to take one of the remaining Champions League spots, with Chelsea visiting Leicester City next Sunday while Arsenal travel to Burnley and Spurs host Everton.