Champions League:Barcelona coach Josep Guardiola believes seeing off Chelsea to reach this year's Champions League final will be a difficult challenge. The Primera Liga leaders will face Guus Hiddink's side next after they brushed aside Bayern Munich and the Blues got the better of Liverpool.

The pair will now meet in the semi-finals of the competition just two games away from an appearance at this year's final in Rome on May 27th.

Guardiola knew he would face either Chelsea or Liverpool in the semis, but now concedes he did not have a preference.

"I don't think we had any preference between Liverpool or Chelsea," he said. "Maybe Chelsea are more attacking, but Liverpool are very disciplined in defence.

"Either way, we have a tough opponent and we have got to accept that it is Chelsea and not Liverpool. Liverpool would not have been any easier, but Chelsea is hard enough."

Chelsea midfielder Michael Ballack believes the Blues have a 50-50 chance against Barca after booking their place in the last four with a remarkable 7-5 aggregate victory over Liverpool.

Barca are the bookmakers' favourites, having easily disposed of Bayern Munich 5-1 on aggregate but Ballack is confident ahead of the encounter, expressing his belief that his team-mates will be buoyed by their Liverpool scalp.

The German told Sky Sports: "Everybody knows about the strength of Barcelona, you could see it in the quarter-final against Bayern Munich, especially in the first leg when they scored four goals.

"So we know what to expect. I think our chances our 50-50. We are a strong team. We won against Liverpool and that gives us a lot of confidence."

Blues midfielder Frank Lampard also expects a stern test. "(It will be) very tough. Everyone is tough now, but probably no one more so than them,” he said today.

"They have got some outstanding individuals and probably the best player in the world in (Lionel) Messi.

"If we get our minds right and prepare right then we have a chance."