Barcelona showed the standard Manchester City need to reach if they are to succeed in the Champions League, according to midfielder Fernandinho.
The La Liga champions beat City 4-0 at the Nou Camp on Wednesday with Lionel Messi scoring a hat trick as Barca punished individual errors from Pep Guardiola's side.
Fernandinho slipped in the box to gift the ball for Messi's opener, while goalkeeper Claudio Bravo was sent off for a deliberate handball after gifting a clearance straight to Luis Suarez.
The Brazilian believes the result was harsh on City but says they need to learn from the defeat.
"The first goal was unlucky of me, I slipped in the box and Messi scored the goal," he told reporters. "We know they are dangerous -- they have three great forwards and they scored three more goals.
"It's that level we want to reach. We will learn from these mistakes and I hope for the next game we can play better and of course get a better result.
"The performance was good and the result didn't reflect exactly what was the game during the 90 minutes because even with 10 players we pressed high to keep the ball, to play between each other.
"But, of course, what counts in the end is the result and we are unhappy about that. We have to work now for the next game to be different."
After winning their opening 10 games of the season, City are now without a victory in any of their last four matches.
But Fernandinho says they have been playing well -- particularly in last Saturday's 1-1 draw with Everton when Kevin De Bruyne and Sergio Aguero both missed penalties -- and says they are confident that results will improve, starting with Southampton on Sunday.
"We are playing good, everyone is confident. The last four games we didn't win but these things can happen in football," he added.
"If you see the last game at home against Everton, they shot twice and scored a goal. Sometimes you cannot explain football.
"The most important thing now is just to keep on working, keep doing what we are doing. We are playing good.
"I believe in my players, in my teammates -- I have a lot of trust in them and this is all that matters.
"We have a long way to go until the end of the season. We have a tough game on Sunday and we'll get ready for that. And for the next game at Barcelona at home, we want a different result."