But after seeing Liverpool fight back from the same scoreline to beat Barcelona 4-3 on aggregate last season, Gnabry said postmatch that Bayern won't let up.

"Three goals should give us a lot of confidence," he said. "We need to be prepared for the second leg and we can't take it serious enough.

"We saw last season with Liverpool beating Barcelona, we know we have to be careful and focus."

Despite the daunting challenge, Chelsea manager Frank Lampard said his team will vow to fight in two weeks at Allianz Arena.

"In the bigger picture we saw there is a lot of quality in their team," Lampard said after the match. "There is a lot to them. But we can't look back on anything.

"We are fighting for the top four [in the Premier League] and we have to go to Munich and show a lot of pride. I will keep working."

Lampard added that his players need to use the loss as "positive effect."

"It might not feel like it this evening. A lot of players there haven't played it, or maybe a few years ago. When you have an eye opener the only answer is to just look at yourself."