Pep Guardiola doubts whether his Manchester City side are good enough to win the Champions League this season.
Last season's Premier League winners were forced to come from behind to defeat Schalke 3-2 in Germany in the first leg of their last-16 tie on Wednesday.
City scored twice in the last five minutes despite having only 10 men following Nicolas Otamendi's red card.
"To go away and score three goals, the way we start, the way we finish, the way we react at half time - I am more than delighted," said Guardiola. "But it's not enough in this competition. We gave them the first goal, we gave them the second goal and the red card.
"We need to improve. I don't know how far we can get but we are nice to watch."
City took the lead through Sergio Aguero but Schalke equalised in controversial circumstances when Otamendi was adjudged to have handled in the area. The penalty was only awarded after a four-minute delay while officials consulted VAR.
After Schalke had scored a second spot-kick, Leroy Sane and Raheem Sterling grabbed late goals to leave City in pole position to reach the quarter-finals.
Sane said afterwards: "We knew it would be a tough game here, like it always is in the Champions League. In the end, we did it. We scored three goals away from home and that was the most important thing, to score goals away. Now, we'll see what happens in the return."
Manchester City can be backed at 2/1 to win the Champions League outright and at 1/4 to beat Chelsea at Wembley on Sunday in the EFL Cup final.
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