Bayer Leverkusen coach Xabi Alonso said on Monday he believes his team can pull off an "epic" comeback against Bayern Munich in the Champions League despite trailing 3-0 from the first leg and losing Florian Wirtz to injury.

Wirtz has been Leverkusen's midfield creative spark this season but was ruled out for "several weeks" with an ankle tendon injury sustained over the weekend ahead of Tuesday's return leg in the last-16 tie.

A poor performance last week in Munich left Alonso's men up against it, but the Spaniard said his side had "nothing to lose" against the German giants.

"Sometimes from a big, difficult situation, something epic is created. Tomorrow, it could be an epic game for us. We know it's not easy, but we must believe," Alonso told reporters.

"Only Bayern can lose something. One hundred percent of Bayern fans think they're going to go through -- we can only win. Many unexpected things happen in football."

In the 2005 Champions League final, Alonso helped Liverpool fight back from 3-0 down against AC Milan at half-time to level at 3-3 and force extra time.

Alonso scored the equaliser that night in Istanbul, tapping in after his spot-kick was saved, before Liverpool went on to win on penalties.

"This game could be another dimension for us. It could stay with us, in our individual history, for a long time," the 43-year-old said.

"We must play with passion, heart, aggression and with our heads -- it's a chance we might not have again in our career."

He added: "The team believes because we've done something more difficult. We won the Bundesliga last season without losing a game -- for me that's more difficult.

"It's all in, make or break, do it or we go home."

Leverkusen centre-back Jonathan Tah said he could feel the belief among his teammates, insisting "it could be a chance to write history".

Bayern manager Vincent Kompany said he did not waste any time deliberating whether to dig in for a draw, with his side well ahead on aggregate.

"When you're Bayern coach, it's mentally a bit easier. You always want to win. When we play a game, we go in with the goal of winning it."

Kompany wished Wirtz a speedy recovery and said Leverkusen had "plenty of other players with quality across the park."

Bayern are also dealing with their own major absence, as captain and goalkeeper Manuel Neuer has been ruled out with injury.

In his place comes inexperienced Jonas Urbig, 21, who will be starting just his second game for Bayern.