Pep Guardiola said Manchester City will emerge stronger from losing their first game of the season in the 2-1 defeat to Shakhtar Donetsk.
City were already assured of finishing as Group F winners and with one eye on Sunday's Premier League Manchester derby against United, Guardiola rested his entire first-choice back four.
Shakhtar then capitalised on uncertainty in the City defence with Bernard firing the home side ahead before 'keeper Ederson gifted the hosts a second - Ismaily taking advantage to tighten the Ukrainian champions' grip on a last-16 spot before Sergio Aguero scored a late penalty for the visitors.
The result spoiled Guardiola's milestone 100th appearance as manager in the competition, but he was determined to focus on the positives that he and his players will take from the experience.
"It hurts. It is never nice to lose a game," he said. "But we have said many times we cannot win all the time, we are going to lose games. Today was the first.
"We needed to lose a game. It will be good for the club, for all of us and the media. People say things when you win a lot and you can forget that now.
"We saw many good things but we made mistakes and we are going to improve on that. Football is how you recover in the good moments and bad moments to stay stable."
Guardiola was thrilled with the performance of some of his younger second-string players.
"I'm so pleased for Tosin (Adarabioyo), Phil (Foden) and Brahim (Diaz) and how well they played," he said.
"We came here to win. We couldn't but we were trying until the end to do so. I'm happy for the performance.
"Now we are going to rest, come back tomorrow and prepare for the game (against Manchester United)."
However, the Spaniard refused to be drawn into billing City as Champions League favourites heading into Monday's last-16 draw in Switzerland.
"It always happens when the draw is made they talk about it but it depends how the team arrives at that moment, on that day.
"Maybe you are good today but in February, you're a disaster. Or the opposite. It will be tough. The contenders are tough but we are going to try."