Antonio Conte hinted he was not happy with Eden Hazard's work-rate after substituting the Belgium star in Chelsea's 2-1 defeat at Manchester United.
Hazard was brought off in the 74th minute of the contest at Old Trafford with the scores still locked at 1-1.
United scored the winner shortly after with Jesse Lingard heading home a cross from Romelu Lukaku, who added an assist to the goal he netted to cancel out Willian's opener.
Hazard had set up Willian for the Chelsea goal, but Conte suggested that his influential forward had failed to maintain his high standards in the second half and that his withdrawal was merely a tactical decision.
"No Hazard [is not injured], no," he told a news conference. "It was a tactical decision.
"You have to keep the same performance for 90 minutes, we didn't have a great balance, and every single player has to try to work with the ball, without the ball, otherwise we lose our balance.
"I think he'd finished his energy because the first half he ran a lot. The second half he started the same way, but when I see a player is a bit tired, my task is to find a different solution."
Conte opted to start with Alvaro Morata up front instead of going with Olivier Giroud or employing Hazard as a false nine as he did in the midweek Champions League draw against Barcelona.
The Spain striker hit the crossbar and had a goal harshly ruled out for offside, but Morata – who is without a league goal since December – again largely underwhelmed.
Explaining his decision, Conte said: "He played for 90 minutes, like the other players they tried to put everything [in] and give their all.
"For sure he can improve. I can take different decisions game by game. I took this decision to find the balance."