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 tomorrow's semifinal meeting with weekend victories, Barcelona prepared for its European showdown with Chelsea by only narrowly avoiding a Spanish league defeat on 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 today'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.

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.

Manchester United's rivalry with Arsenal has been less intense in recent seasons as the Gunners have faded from contention for major honors. But that could change when the teams go head-to-head at Old Trafford.

United showed its attacking range when it rallied from 0-2 down at halftime to beat Tottenham 5-2 on Saturday, with Cristiano Ronaldo and Wayne Rooney each scoring twice.

The pair is almost certain to start again against the Gunners, who had a 2-0 win over Middlesbrough on Sunday that was so straightforward that manager Arsene Wenger was able to replace captain Cesc Fabregas with more than 20 minutes left.

The key midfielder scored both his team's goals and could make use of the extra rest.

(Agencies via Shanghai Daily April 28, 2009)