Chelsea will go into the Europa League semifinal second leg with a foot already in the final, but Rafa Benitez will ensure there is no complacency within the ranks despite the Blues being on the verge of making another European final.

The English Premier League side lead 2-1 going into the second leg at Stamford Bridge, after David Luiz's late strike gave them the advantage.

Basel need to score at least two goals at Stamford Bridge to have any chance of progressing to the final, and the Swiss side have shown enough quality in the tournament to make Chelsea wary of a fightback.

Tottenham had to come back from two goals down in the quarterfinal first leg at White Hart Lane, and with Chelsea's defence not as good as last season, there is certainly a slight chance of an upset, something that Benitez is well aware of.

"As a manager you want to win every trophy if you can," Benitez said. "We have an opportunity but my concern is that we will be thinking we are in the final. It's not the case.

"We play against a very good team that has scored goals away, so everybody has to realise it will be difficult.

"Hopefully I will be wrong and we can score a lot of goals, but first we have to win and afterwards we can think about the final.

"I think they will come trying to score. They did it against Tottenham. I am sure they will be offensive and push.

"We saw that in the second half and I think it will be the same approach. It's the only way for them to qualify.

"I am concerned but I am not afraid. We know they are a dangerous team, we know they are strong and score goals away.

"But we know we have a good team and are so close to the final we have to be focused and not make mistakes. I have a lot of confidence in my players."

Chelsea will be without Ashley Cole, who is suspended, while Demba Ba is ineligible having represented Newcastle earlier in the tournament.

Benitez will also have to take into account four players - David Luiz, Ramires, John Obi Mikel and Ryan Bertrand -- who are one booking away from missing the final at the Amsterdam Arena, if they do qualify.

"We have qualified for the semifinal," Benitez said. "It's a fantastic achievement in a busy season and a transition period. We will try to do our best and be in the final.

"The main thing is to win and qualify for the final. We will try to do it with the best team possible for this game. It doesn't matter about the yellow cards."

Basel will have to do without their best defender Aleksandar Dragovic, who is suspended, while Kay Vosler is ruled out through injury.

All eyes will also be on Frank Lampard, if he gets a game, with the midfielder just one goal away from equaling Bobby Tambling's club record of 202 goals. Nothing will please the veteran more than tying and possibly even breaking the record in front of the home fans.

Expected lineups: Chelsea: Cech; Azpilicueta, Cahill, Terry, Bertrand; Luiz, Lampard; Moses, Hazard, Benayoun; Torres.

Basel: Sommer; Degen, Schar, Sauro, Park; Geoffroy, Stocker, Frei, Salah, El Nenny; Streller.

Prediction: 2-1 to Chelsea (4-2 aggregate victory).