If playing in front of a full and frenetic Weserstadion had threatened to cause FC Barcelona some difficulty, the Spanish champions struck in either half through Deco and Ronaldinho to secure a 2-0 victory against Werder Bremen in Group C.
Despite the prospect of lining up against one of the world's great attacking teams, Bremen coach Thomas Schaaf stated his intent by sticking to his favoured 4-4-2 formation. Missing from that system was suspended striker Miroslav Klose, scorer of two goals in Saturday's rousing 5-1 defeat of 1. FC Kaiserslautern, with the German international's place alongside Ivan Klasnić going to Nelson Valdez of Paraguay.
It was a bold move which seemed to promise goals, and one almost arrived in the second minute following a blistering start by Bremen. Klasnić, the Croatia forward, released Valdez who unleashed a left-footed shot from a tight angle which almost squeezed under Víctor Valdés, only for the Barça goalkeeper to keep the ball out with his legs. Roles were reversed in the tenth minute, Valdez creating an opportunity for Klasnić which Valdés again repelled.
Like Bremen, the visitors enjoyed a fine weekend result, Samuel Eto'o scoring both goals in a 2-0 success against RCD Mallorca, and coach Frank Rijkaard saw no reason to alter his side. He was rewarded in the 13th minute as Giovanni van Bronckhorst and Ronaldinho combined down the left to work the opener.
With his path to goal blocked by a posse of defenders, the Brazilian found Eto'o who in turn touched the ball first time to Deco on the edge of the area. Although the Portuguese international's effort lacked pace, it took a significant flick off Frank Baumann and trickled past wrong-footed goalkeeper Andreas Reinke.
A superb 27th-minute counterattack almost brought Bremen level, though Klasnić failed to make contact with Valdez's inviting centre from the right. An even more presentable chance was fashioned soon after, Klasnić dispossessing Juliano Belletti and crossing low to the far post where Valdez could only turn the ball over when a more composed touch would surely have restored parity.
The visitors' goal continued to lead a charmed life in added time, Frenchman Johan Micoud smashing a left-foot volley off the post, enabling Ronaldinho to cut a relaxed figure as he swapped shirts with countryman Naldo as the players departed for a well-earned 15-minute break. Naldo, the Bremen centre-back, was not so charitable just after the restart, firing in a free-kick from distance which provoked more reaction from the crowd than it did Valdés who was able to watch it whistle wide.
Although Baumann could do nothing about the deflection which allowed Deco to open the scoring, it was a defensive lapse which gave the Portuguese a sight of goal in the 49th minute. This time, however, the former FC Porto man could only strike a shot against the post. Barcelona looked more assured following the half-time introduction of Edmílson for Belletti and Bremen were reduced to half-chances as they sought a way back into the game.
Rijkaard made another important change in the 66th minute, bringing on Argentinian prodigy Lionel Messi, who ten minutes later was winning a penalty following Christian Schulz's illegal challenge. Ronaldinho stepped up and whipped the spot-kick into the right-hand corner of Reinke's goal to ensure a winning start for a team who appear to have the credentials to end their long wait for further European glory.