Manchester City boss Pep Guardiola has said he substituted Vincent Kompany at half-time in the 1-0 EFL Cup defeat to Manchester United because the defender told him he was tired.
City captain Kompany, 30, has suffered repeated injuries over in recent seasons but made a second successive start in Wednesday's derby after playing for 78 minutes in Sunday's 1-1 draw with Southampton.
He was replaced by Aleksandar Kolarov at the break at Old Trafford, though, and Guardiola told reporters: "He told us he is tired and was not ready to play the second half.