This precious result was just one element in an astounding night for Liverpool. They had initially been outclassed in the delicate facets of the game but are now on the verge of knocking out the holders and entering the quarter-finals. Such was the transformation that they were a far sounder line-up by the end than psychologically fragile Barcelona, who conceded two hapless goals.
In its own manner it was a recovery as uncanny as the overhauling of the 3-0 deficit to Milan before winning this tournament in 2005. Last night the task was to resist the sense of inferiority that might have been stamped indelibly on to Liverpool minds when Barcelona's panache was at its most hypnotic. In reality that stretch of the game was short, but the flakiness of Frank Rijkaard's line-up could never have been exploited without the self-belief of Rafael Benítez's squad.
On such a disconcerting evening it was perversely apt that John Arne Riise and Craig Bellamy, who had such severe differences during the Algarve altercation a week ago, should be clasped together when the Welshman laid on the 74th- minute decider for the Norwegian. That was not to be overshadowed and a late free-kick by Deco bounced off the far post.
Barcelona were as frail in defence as they were delicately beguiling in attack. Liverpool, outplayed and exposed for prolonged spells, responded with conviction whenever the pressure eased because the champions of Spain were so insecure. Bellamy's equaliser must have astonished his team-mates even as it delighted them, but they also made sure it was a turning point.
Xabi Alonso sent a free-kick to Steve Finnan and when his cross was met by the forward his header flew straight to Victor Valdés. The goalkeeper was unaccountably positioned behind his line and therefore conceded a goal. Bellamy, gleeful over the current bout of notoriety, celebrated by pretending to swing a golf club.
Barcelona allowed that aberration to undermine them. They never regrouped and bore out claims that the Rijkaard era is winding down by flailing and flapping. In mitigation, their mood of shock was natural even if it should not have turned into the team's distinguishing characteristic in the second half.
Rijkaard's side had briefly seemed to be gliding on a higher plane. Benítez, the world authority on beating Barcelona since his days with Valencia, had his credentials questioned at first. The system had a makeshift air, with Barcelona relishing access to the wings that Liverpool had meant to deny them.
On the left Alvaro Arbeloa made his first start, with Riise in front of him, but it never looked as if Lionel Messi was outnumbered. The rhythm of Barcelona's passing and movement opened up space. In an even-handed way Rijkaard's players kept Finnan and Steven Gerrard in as much difficulty on the Liverpool right.
A dive by Ronaldinho in the 13th minute was shabby conduct, but the Brazilian's capacity to get into a penalty-box position was significant. Barcelona had free rein in the 14th minute, however. Gerrard could not stop Gianluca Zambrotta from crossing, Arbeloa failed to climb high enough to connect with the ball and Deco, free of Riise, headed in at the far post.
Deco was soon shooting against Pepe Reina after Messi had put him through and few would have guessed that Barcelona could be denied. Liverpool, though, had been bright when they got a loan of the ball and perhaps reminded themselves that Barcelona view defending as a task unworthy of them.
The second half opened with Liverpool far more effective in the system Benítez had set out. Rijkaard's reaction was characteristic, if reckless, and defensive resilience vanished from their midfield as Andrés Iniesta took over from Thiago Motta.
Liverpool had the briskness of men reprieved and the visitors went on the attack themselves with optimism. Barcelona yearned for transformational virtuosity but Rijkaard's men had become far better at bringing havoc down upon themselves. When the substitute Ludovic Giuly passed back into his own area Valdés impetuously picked the ball up to give away a free-kick. It was touched to Gerrard and, although the goalkeeper blocked his drive, Liverpool were so full of verve that Arbeloa swept in a dashing cross which Dirk Kuyt headed on to the bar.
Barcelona did get an invitation to regain the lead immediately before they fell behind, however. In the 73rd minute Javier Saviola wormed his way through and, when the ball ran free after being blocked by Reina, Messi seemed set to finish until Arbeloa got in the way of his effort.
Moments later Gerrard fed Kuyt and, although the Dutchman miscontrolled, Valdés hesitated and Rafael Márquez inadvertently knocked the ball down to Bellamy, who squared for Riise to hit the net with a right-foot drive. In all the fundamentals of football competitiveness Liverpool had transformed themselves into the superior team for whom this conquest in Barcelona was only natural.