Pep Guardiola has described Manchester City as Champions League "teenagers" and warns they cannot take their place in the quarter-finals for granted ahead of Tuesday's game with Schalke.

City hold a 3-2 lead from the first leg of the last 16 and are expected to progress against a side who sit 14th in the Bundesliga and lost 4-2 to Werder Bremen last Friday.

Despite their impressive domestic success since the Abu Dhabi-backed takeover in 2008, City have yet to progress beyond the semi-final stage in Europe's elite competition and Guardiola has suggested previously that they are not ready to win it.

Speaking on Monday, he conceded they are a long way from matching the continental success of the likes of Liverpool and Manchester United, who have eight titles between them, even though he insists they are eager for success.

"We could win it and make another step. You need 20 or 50 years. We can make a partial step forward but to compare with those kinds of teams, one silverware doesn't change it. We are teenagers in this competition," he said.

"It's not an excuse - we want to win it, we push ourselves and it will be not good if we don't go through. You have to dream, you have to point as high as possible but there are a lot of teams thinking the same: United, Tottenham are there. We spoke many times with the players and say you have to have the desire to compete with the best players in Europe."