Barcelona must guard against its form dipping at just the wrong time to prevent it challenging England's domination of the Champions League. While defending champion Manchester United and Arsenal warmed up for Wednesday's semifinal meeting with weekend victories, Barcelona prepared for its European showdown with Chelsea by only narrowly avoiding a Spanish league defeat Saturday - Thierry Henry scored with four minutes left for a 2-2 draw against Valencia. The end of a seven-match winning streak was hardly ideal preparation for Tuesday's first-leg meeting with Chelsea, which continued its impressive form under temporary coach Guus Hiddink with a hard-fought 1-0 win at London rival West Ham 1-0. But coach Pep Guardiola still thinks his relentlessly attacking team should be fine. “We finished like bulls,” Guardiola said. “We're a machine.” Many neutrals are hoping he's right and that Barcelona can get past last season's runner-up. England has provided nine of the past 12 Champions League semifinalists in an unprecedented domination of the continent's top club competition. Tuesday's game at Camp Nou will go some way to proving whether Barcelona, which has scored 94 goals in 33 games to lead the Spanish league by seven points, is good enough to add a third European Cup title to its collection - three years after its last. “The best team in Europe,” Hiddink said of Barcelona. “Or the world.” Samuel Eto'o, Lionel Messi and Henry, who scored 10 goals against Chelsea in his eight seasons with Arsenal, will line up again to pressure a defense missing suspended left back Ashley Cole and injured central defender Ricardo Carvalho. With Carvalho out, Chelsea captain John Terry should play alongside Alex, with Branislav Ivanovic one of the contenders to replace Cole and attempt to shackle Messi. Hiddink rested striker Didier Drogba, Michael Ballack, Michael Essien and Alex at the weekend, only bringing on the midfield pair late to shore up the side. The win kept Chelsea in contention for the Premier League title, although Manchester United and Liverpool are still ahead of the Blues. Chelsea's most likely route to a trophy this season appears to be the Champions League or next month's FA Cup final against Everton. Manchester United faces Arsenal at Old Trafford on Wednesday.