London, September 13 :

FC Barcelona and Chelsea picked up victories on Tuesday on the opening day of the group stage in this season’s Champions League.

Defending champion Barcelona routed Bulgarian team Levski Sofia 5-0 at Camp Nou stadium on first-half goals by Andres Iniesta and Ludovic Giuly, and three in the second half from Carles Puyol, Samuel Eto’o and Ronaldinho.

“We knew we couldn’t relax because any team can beat you,” Puyol said. Chelsea beat Werder Bremen 2-0 on goals by Michael Essien and Michael Ballack. Ballack’s penalty was his first goal for Chelsea since moving from Bayern Munich.

“I’m happy, but it was a difficult game for us,” Ballack said. “Of course it was the first game, and nobody’s knows how we’d start. “I knew Bremen was a very good team, and it was important we scored the first goal.” Ballack took the penalty instead of Frank Lampard, who has missed several key penalties in recent games. “Before I spoke with Frank and he said you can take it,” Ballack said.

Chelsea and Barcelona are both in Group A and will play in back-to-back games on October 18 and 31. “It was an important victory,” Chelsea manager Jose Mourinho said. “It was the first game and it was against a team we know will contest every game and every point and can give a difficult time to Barcelona.”

Bayern Munich bounced back from a sluggish start with a strong second half to bury Spartak Moscow 4-0 in Group B. Claudio Pizarro scored the first goal in the 48th, and Roque Santa Cruz padded the lead in the 52nd. Bastian Schweinsteiger and Hasan Salihamidzic wrapped up the scoring later in the half.

In the other Group B match, Marco Caneira’s goal in the 64th lifted Sporting Libson over Inter Milan. Group C is shaping up as the weakest in the Champions League with all four teams — Galatasaray vs Bordeaux and PSV Eindhoven vs Liverpool — failing to score on Tuesday.

In Group D, Fernando Morientes scored three goals — in the 34th, 39th and second-half injury time — to lead Valencia to a 4-2 victory at Olympiakos. Raul Albiol scored the other for Valencia. Michalis Konstantinou and Nery Castillo scored for Olympiakos.

In the other group game, Roma overwhelmed Shakhtar 4-0 on second-half goals by Rodrigo Taddei, Francesco Totti, Daniele De Rossi, and David Pizarro.