Liverpool manager Rafael Benitez says anything can happen in the second leg.
"It's important to know that, now, we are in a very bad position," he said, "but that means we have nothing to lose. We can approach the game without pressure and anything can happen. That's football. The players can play better if they play without nervousness and anxiety."
Benitez hopes Chelsea will be overconfident.
"Chelsea are playing well and they have a lot of confidence," he said. "They will think it's nearly done, but that's normal. We have to approach the game thinking we can still get through, but Chelsea will go into it thinking it will be very difficult for us. They'll be trying to score, to finish the game."
The weekend results give the Reds hope. They pounded Blackburn Rovers, 4-0, while Chelsea got a scare, going up 4-0 at Stamford Bridge against Bolton Wanderers before the visitors pulled to within 4-3 with three unanswered goals.
Chelsea will be without suspended captain John Terry, Liverpool welcomes back Javier Mascherano back in midfield, where it lost the first-leg battle.
Finally, it should noted that Liverpool has already Chelsea once this season at Stamford Bridge, winning, 1-0, in October to snap the Blues' 86-game home unbeaten streak.
Chelsea -- 1-Cech; 2-Ivanovic, 33-Alex, 6-Ricardo Carvalho, 3-A.Cole; 13-Ballack, 5-Essien, 8-Lampard; 21-Kalou, 11-Drogba, 15-Malouda.
Liverpool -- 25-Reina; 17-Arbeloa, 37-Skrtel, 23-Carragher, 12-Fabio Aurelio; 14-Xabi Alonso, 20-Mascherano; 18-Kuyt, 8-Gerrard, 11-Riera; 9-Fernando Torres.
Referee: Luis Medina Cantalejo (Spain).