City saw off their League Two neighbours 2-0 at the Etihad Stadium to reach the fifth round.

After benefiting from an early own goal from Alfie Dorrington, City went through the motions before Marc Guehi made victory certain with his first goal for the club late on.

Asked if he was pleased with the performance, Guardiola said: “No. We didn’t read the spaces where they were. With the spaces in attack it depends on how they defend it and we didn’t read it.”

He added: “That is the reason why the game was boring. The only good news is we go through. That’s all.”

Guardiola made nine changes as he took the opportunity to rotate his squad.

With a rare full week to rest before they resume their Premier League title challenge, the Spaniard now intends to give his players a few days off.

He did not want to use tiredness as an excuse for a flat performance, however.

Guardiola said: “It would be nice for me to say mentally we’re exhausted, we’re tired, it has been a tough two or three weeks for many reasons.

“But it’s our job. The calendar says to play every few days.

“We just didn’t read where the spaces were and everything was flat and slow and not good.”

One positive for City was the return of England defender John Stones, who made his first appearance in more than two months after recovering from a thigh injury.

Guardiola said: “He’s back. He still needs time, he’s not the John Stones that we knew but his body language was really good in terms of the press and aggression. It’s important that he played 65 minutes.”

Salford were thrashed 8-0 by City in the competition last season and could reflect with pride on their resilient performance.

Their attention now returns to their League Two promotion challenge.

Manager Karl Robinson said: “I said before the game this football club has improved every year.

“We’ve put an awful lot of effort in behind the scenes and we felt we were coming here today with a much stronger squad, as a better club.

“I think the players showed that and it’s about us using this. Last year we couldn’t use it but we can use this as a benchmark to move forward.

“I hate losing but you have to accept it. I think the way we’ve lost today is testament to the players.”