With the game seemingly heading towards a 1-1 draw that would have taken the Italian champions through after Samuel Eto'o had levelled for the home side to cancel out Andriy Shevchenko's opening goal, the Brazilian playmaker picked up Eto'o's pass just outside the penalty area and cut inside Alessandro Nesta before unleashing an unstoppable left-foot shot that flew high into the top corner and sent the 90,000 Camp Nou fans into ecstasy.
 Barcelona were still without long-term injury victims Gerard López, Edmílson, Thiago Motta, Gabri García and Sylvinho, although Ludovic Giuly returned. Milan, meanwhile, welcomed Kakha Kaladze, Shevchenko, Serginho and Andrea Pirlo back into their starting lineup.
 Although Milan's tactical plan and fluid passing dominated the first half, it was the home side who should have scored first. Brazilian full-back Juliano Belletti had needed a late fitness test on an achilles injury but created danger as early as the fifth minute, cutting back on to his left foot and delivering a lovely drifting cross that Deco headed powerfully beyond Milan goalkeeper Dida only to see the ball shave the post.
 The escape spurred on the Italian champions, who controlled play by keeping possession and playing cleverly on the break. In a forewarning of what was to come, Shevchenko turned Carles Puyol and found the galloping Serginho, who in turn crossed for Kaká but Víctor Valdés did excellently to hold the volley.
 But by the 17th minute the visitors had the lead. Pirlo had time to spot Shevchenko's turn and sprint and his pass caught out Oleguer Presas. The Ukraine striker eluded his marker to burst free and gave Valdés no chance with his composed finish.
 Barcelona, however, refused to crumble and little by little edged further upfield as Ronaldinho flashed two shots wide, while it took a solid tackle from Nesta to block Eto'o's determined run. Deco then slid an opportunistic shot just wide following neat play between Giuly and Eto'o.
 Barcelona's reward was the goal which hauled them back into contention, with the bizarre component an accidental bump of Ronaldinho's head against Cafu's mouth that left the Milan player off the pitch. Referee Urs Meier quickly allowed play to restart and a quick pass from Rafael Márquez found Xavi Hernández for a lovely pass into the path of Eto'o, who crashed his shot high into the net.
 Finally the crowd and the home team raised their game and Cameroonian international striker Eto'o collected Ronaldinho's flick-on to thump a left-footed shot just wide as the first half ended. Milan's response was to defend still deeper and rely on counterattacks, handing momentum to the home side.
 Ten minutes into the half Dida had to produce two outstanding saves to keep Milan in the game. First he fumbled Deco's free-kick after Ronaldinho had been fouled, but dived to save Xavi's follow-up effort superbly and moments later blocked a cleverly worked close-range shot from Giovanni van Bronckhorst.
 But the save of the night came at the other end on the hour when Cafu's vicious volley was pawed away from the top right-hand corner of his goal by Valdés. In the main, however, it was Barça who looked the more likely winners, but Milan looked to have held firm before Ronaldinho's stunning effort.