Liverpool had 96 minutes to break Atletico Madrid down at the Metropolitano three weeks ago and they couldn't do it.
So what chance at Anfield when Diego Simeone's team will be even more entrenched?
The travelling fans will be in their element but there are reasons for Jurgen Klopp to think that he can devise a masterplan to see his side through. Here, Sportsmail looks at the challenge facing him.
Living on reputation?
The first thing to point out is that this is not the old 'they shall not pass' Atletico.