Massimiliano Allegri was angry with the way Juventus squandered a lead and defended his decision to keep Dusan Vlahovic on the bench in a 1-1 draw at Fiorentina.
Arkadiusz Milik marked his first Juve start by scoring his second goal in as many games at Stadio Artemio Franchi, but that proved to be a false dawn.
Christian Kouame equalised with a goal on the break after Weston McKennie passed when he should have tried his luck at the other end.
Mattia Perin saved Luka Jovic's penalty late in the first half after Leandro Paredes was adjudged to have handled in the penalty area on his Bianconeri debut.
Allegri withdrew Angel Di Maria at half-time as a precaution and opted to send on Moise Kean rather than in-form ex-Fiorentina striker Vlahovic as Juve made it five Serie A matches without defeat this season.
Juve head coach Allegri was not impressed with the manner in which his side were caught out for Kouame's strike.
He said: "Getting angry is an understatement, you should not concede that goal. At that moment we had to kill the game."
Allegri added: "In the second half we dropped [back], but the thing to improve absolutely is that when you have the ball when leading.
"From that ball [from McKennie] then came the corner [for Juve] and the 1-1, which changes everything."
Vlahovic had scored four goals in as many games but Allegri felt he needed a rest ahead of a Champions League opener at Paris Saint-Germain on Tuesday.
He said: "He had played several games and Milik could give us an extra hand. We wanted him to rest, then there were some forced changes."