MANCHESTER -- Pep Guardiola said the match ball was "unacceptable" after Manchester City scraped past Wolverhampton Wanderers in the Carabao Cup on a penalty shootout.
City were held to a 0-0 draw by the Championship leaders and only made it through to the fifth round 4-1 on penalties after Claudio Bravo saved two spot kicks.
The tie was played with the Mitre Delta EFL, which is different to the Nike Ordem V ball used in the Premier League. Guardiola refused to blame the ball for the performance but he was unhappy with it.
"It is not acceptable, the ball was unacceptable for a high-level competition," he told a news conference.
"It is too light, it moves all over the place, it is not a good ball. It is impossible to score with a ball like that and I can say that because we won, I'm not making excuses.
"All of my players said 'what is that?' I'm sorry Carabao Cup is is not a serious ball for a serious competition. It's marketing, money, ok but it's not acceptable, no weight, nothing.
"One day or two days, but the ball is bad for one year or two years, it's not acceptable. all the players complain."
However, Guardiola was pleased for Bravo, who was the City hero saving penalties from Alfred N'Diaye and Conor Coady.
The Chile international also made a number of fine saves during the game, rescuing City in one-on-one situations from Bright Enobakhare, twice, and Helder Costa.
Bravo lost his place to Ederson after a disastrous first season at the Etihad Stadium in 2016-17, but has been drafted in for the League Cup with Guardiola making nine changes from the side that beat Burnley in the Premier League on Saturday.
Guardiola said: "It was not easy last season for him but he's a keeper at a high level -- you can't be at Barcelona and Chile without being at a high level. He deserved the performance, without him we would not be in the next round.
"For Claudio, he's here to play but he's a good professional and he has to be ready -- you never know what happens in football. But it's not easy to come in for games like this."
City midfielder Ilkay Gundogan played the full 120 minutes, but Guardiola said that the German international, who missed the second half of last season with a cruciate knee ligament injury, had picked up a knock.
"Gundo finished with some problems, we hope it's not dangerous," Guardiola added. "It's so demanding the physicality. I don't know if it's serious, we'll see tomorrow."