AC Milan staged a classic counter strike to take the lead at the Camp Nou against the run of play and they extended their lead to stun the home fans in the second half.
Coco rose unmarked to head in the 45th minute.
The goal came against the run of play.
Barca had come close to taking the lead in the 10th minute when Simao Sabrosa set up Patrick Kluivert in front of goal. The Dutch star was derided as a Milan player after a poor season in Serie A and he made a glaring miss with his weak shot.
The next best chance fell to Rivaldo in the 35th minute when Sabrosa - excellent on the night - bent in a cross which the Brazilian headed wide.
Kluivert could find no way to get the ball on target as Barca continued to dominate as Milan protected their lead. Good approach play was unrewarded as Kluivert lost confidence when he had the chance to get revenge on Milan.
In such a game Barca - with poor defending very much still part of their play - were always vulnerable to the break which would kill the game.
Milan delivered it in the 71st minute when Francesco Cocu raided down the left win to cross for Oliver Bierhoff to head in. Barca are in danger of going out of the Champions League after two successive defeats and they still have to play at Leeds and Milan.
All Content is Copyright © 2000 WorldSoccerNews.com. All rights reserved. This material is intended solely for personal use. Any other reproduction, publication or redistribution of this material without the written agreement of the copyright owner is strictly forbidden and any breach of copyright will be considered actionable. 2000