Bayer Leverkusen will show they are a complete team against Bayern Munich in the Champions League even without the injured Florian Wirtz, says head coach Xabi Alonso.

Leverkusen confirmed on Monday that Wirtz will miss "several weeks" with an ankle ligament injury, having come off during Saturday's Bundesliga loss to Werder Bremen.

The news of Wirtz's injury is a major blow to the German champions, who lost 3-0 to domestic rivals Bayern in the first leg of their Champions League last-16 tie last week.

On Tuesday, Leverkusen will aim to become just the fifth side in Champions League history to lose the first leg of a knockout stage tie by three or more goals and still progress.

The only teams to ever do so are Deportivo de La Coruua in 2003-04 (versus Milan), Barcelona in 2016-17 (against Paris Saint-Germain), Roma in 2017-18 and Liverpool in 2018-19 (both against Barcelona).

Alonso does not feel a comeback is beyond his team, even without Wirtz.

"I am really sorry for him because he was in a top moment," Alonso said on Monday. "Now it is a good moment to show we are a complete team and that we can go on without him.

"Once the ball is rolling, many unexpected things can happen. For us, this game is all-in, make or break."

Wirtz, who has scored nine league goals this campaign and set up another 10, has also netted another six times in the Champions League, 

He will also miss Germany's Nations League quarter-final tie against Italy on March 20 and March 23 and is unlikely to return for the DFB-Pokal semi-finals against Arminia Bielefeld on April 1.

While overturning a 3-0 deficit against Bayern is a huge challenge, Alonso says Leverkusen must go into Tuesday's game with self-belief.

"The first thing we have to do is to believe, and for the fans to also believe from the first second that we can do it," the Spaniard said. 

"It is a game of another dimension. We must play with heart, passion and brain. We have a chance and must fight until the end.

"But with a big situation you can also achieve something epic. The injury could also be a boost, to say we fight for the big game but also for Flo."

"The team is convinced we can do it for many reasons but one is that we are in a position where we have nothing to lose. All Bayern fans believe they will go through."