Manchester City boss Pep Guardiola believes facing Napoli in the Champions League tonight could be their biggest test of the season so far.

City's players face a test of their mettle in front of a sold-out San Paolo.

"Tomorrow we have a big, big challenge," he said. "There will be moments to defend, moments when we are going to suffer like never before, and I'm going to see how we react. That's why it's a good challenge for us to see.

"The players know that, they know what they can improve, and that is the mentality to getting there.'

Napoli coach Maurizio Sarri says he "would like to see frightened faces" from City.

Guardiola responded: "Fear? There is no fear, just a lot of respect for the way they play. There should never be fear.

"We are a very young club, we don't have history like Juventus, Barcelona and Real Madrid. We only have four players that have played at this level and a lot of young ones. It's an important game for us to try to grow as a club."

A draw would be enough for City to qualify from their group.

"Why we play for a draw when we can play for a win?" added Guardiola. "We are going to try to win."