Defending champions Barcelona blanked out German league leaders Werder Bremen 2-0 to squeak through to the knockout stage of Europe's premier competition.

In a do or die match for the Catalan club, goals from Ronaldinho and Eidur Gudjohnsen in the first half was enough to secure the victory and book them a place in the last 16 of the Champions League.

Ronaldinho put Barca in front with a cheeky free kick in the 13th minute, which left both the Bremen defense and the keeper gaping after the ball. Four minutes later, Gudjohnsen slammed home a Ludovic Giuly cross to double the lead.

Needing to win in order to avoid being the first European Champions not to reach the knockout stage, Barcelona were quickly off the blocks with Gudjohnsen missing the ball after Guily had done well to cross the ball across the goal.

Tim Wiese then had to dive full stretch to deny Giuly in the 10th minute. However three minutes later Barca were in front with a brilliant free kick by Ronaldinho. Fouled just two meters outside the area, the Brazilian ace stepped up to take the free kick. While everyone, including the Bremen wall and keeper Wiese were expecting him to curl the ball, Ronaldinho drilled the shot below the jumping Bremen wall, shooting past the left-hand post.

Five minutes later Ronaldinho released Giuly on the right wing and a low cross across the goal by the Frenchmen was converted gleefully by Gudjohnsen. Bremen came back strong in the second half with midfielder Daniel Jensen coming close to scoring but hit the post.

Barcelona coach Frank Rijkaard was relieved that his team put up a good performance to win the match. "I'm happy because we had to make a difference tonight and we saw a great first-half performance. The effort the team made was immense so I congratulate my players for their work. This result, and qualification, brings a calmness to the squad", he said.

In other matches, Italian club AS Roma defeated Valencia 1-0 to move into the second round of the competition while Liverpool lost out to Galatasaray 3-2. Results of the other matches played on Tuesday are:

Barcelona 2-0 Bremen

Chelsea 2-0 Levski

Bayern 1-1 Internazionale

Sporting 1-3 Spartak Moskva

Galatasaray 3-2 Liverpool

PSV 1-3 Bordeaux

Olympiacos 1-1 Shakhtar