Defending champions Liverpool FC conceded their first UEFA Champions League goal since September as Luisão's header six minutes from time gave SL Benfica a narrow first-leg victory in their Round of 16 tie at the Estádio da Luz.
The Brazilian defender nodded in Petit's 84th-minute free-kick as the home side's patient approach paid off in a match that had previously seen just one shot on target. Though the game was largely disappointing, the result sets the tie up for a fascinating second act at Anfield in two weeks' time.
Benfica played five across the middle, with Nuno Gomes starting as a lone striker to counteract Liverpool's perceived strength in midfield, although Rafael Benítez sprung a surprise by leaving Steven Gerrard - nursing a dead leg - and Dietmar Hamann on the bench. Instead, the Liverpool manager opted for an attacking formation in which Robbie Fowler returned for his first UEFA Champions League start since 2001.
Benfica's vaunted eagle had barely vacated its perch when referee Konrad Plautz was called into action, booking Luis García for a late tackle on Léo - a rare moment of spark in the tepid early exchanges. The first attacking threat came after 14 minutes from a clever free-kick by Liverpool when Fowler's flick almost found Mohamed Sissoko, only for Benfica to step in and avert the danger. Fowler was again involved ten minutes later as Benfica failed to deal with John Arne Riise's long throw, before Luisão scrambled the ball clear at the expense of a corner.
The hosts finally came to life after 26 minutes when both their wingers combined on the left flank. Simão fed Laurent Robert but the Frenchman, well used to playing English teams after almost five seasons in the Premiership, was foiled by José Manuel Reina who raced quickly off his line to claim the ball. On the half-hour, Sissoko went off on a stretcher following a high challenge from Beto which earned the midfielder a yellow card, Hamann coming on.
Just as the first half was drawing to an appropriately low-key conclusion, Steve Finnan's foul presented Simão with a chance from a free-kick on the edge of the penalty area. The Portuguese international attempted to curl the ball into the top corner but only succeeded in firing it into the crowd to sum up a disappointing period. Luis García passed up the clearest opening of the match soon after the restart, although Benfica also adopted a more adventurous approach. Hamann picked up a booking as he stopped one Benfica foray in the 54th minute, 60 seconds before Luisão calmly dispossessed Luis García after the Spaniard had opted against an early shot.
Another of Benfica's dangerous dead-ball specialists, Petit, followed Simão in wasting a decent opportunity from a free-kick before coach Ronald Koeman replaced Beto with the more attack-minded Georgios Karagounis. Reina then twice had to be alert to deny Benfica - scrambling back to gather Petit's audacious 45-metre lob from under his crossbar before stealing the ball from Luisão after the defender was found unattended by Nuno Gomes's pinpoint pass. Liverpool responded by introducing Djibril Cissé for Fowler and his erstwhile strike partner Fernando Morientes headed over Riise's long throw after 66 minutes.
Liverpool talisman Gerrard came on for Morientes with 13 minutes remaining but Benfica continued to take the game to the holders in the closing stages. Karagounis fired over with ten minutes left but chances remained at a premium until Luisão's timely intervention.