Coach Louis van Gaal admits Bayern Munich's progression to the Champions League quarter-finals is no guarantee Franck Ribery is going to stay.

The German side booked their place in the last eight at the expense of Fiorentina on Tuesday night, their 3-2 defeat at the Stadio Artemio Franchi seeing them through on away goals after the tie ended 4-4 on aggregate.

Mark van Bommel and Arjen Robben scored the second-leg goals, while Ribery played from the start despite having been a slight doubt for the match. He only appeared from the bench in last weekend's Bundesliga draw at Cologne after picking up a knock on international duty with France earlier in the week.

Van Gaal was impressed with the winger's contribution, but knows it will not be easy to convince him to stay.

"If I look at him doing everything to be fit for the game against Fiorentina, then I think he will stay," Van Gaal was quoted by Kicker as telling the Sat.1 television channel.

"If I then read the newspapers I think he won't stay. It is difficult. If he wants to go we should sell him now, because it brings in money and is good for Bayern."

Ribery is under contract until 2011 and Bayern run the risk of losing him for nothing at end of next season.

However, qualification for the last eight will go some way towards convincing Ribery to remain at the Allianz Arena.

He claimed the win showed Bayern have the potential to be very successful.

"It was very important for us to go through," he said. "We knew that it was not going to be an easy game and the weather didn't help us either, particularly in the first half when it was very tough.

"We showed a great team performance with a lot of solidarity.

"As a team, together we can achieve a lot."

Matching last season's achievement in reaching the quarter-finals was a minimum requirement for Bayern, and now the bar is set to be raised even higher amid hopes of a favourable draw in the next round.

"We are happy to have gone through - that was the aim," midfielder Bastian Schweinsteiger told Bayern's official website.

"Now we have got to see if we get the luck of the draw. Maybe we will get another not-so-big opponent."

There was some less positive news for Bayern, though, as Mario Gomez ruptured a muscle in his right calf in last night's match and is set to be out for two to three weeks. Gomez was replaced by Miroslav Klose 30 minutes into the game.

The Germany striker will be back in contention for the Bundesliga clash with his former club Stuttgart on March 27 at the earliest, Bayern confirmed on their official website.

The first legs of the Champions League quarter-finals take place on March 30 and 31.