MADRID - Sergio Aguero produced a scintillating performance as Atletico Madrid put their recent woes aside to stun title-chasing Barcelona on Saturday night.
Aguero scored twice and created Atletico's other two goals as the hosts shook off the dire form that had seen them lose four of their previous six league fixtures, and been knocked out of both the UEFA Cup and Copa del Rey.
Second-placed Barca, who won this corresponding fixture 6-0 last season, scored both first and last through Ronaldinho's brilliant overhead kick and then Samuel Eto'o, but it was not enough to prevent them falling five points adrift of leaders Real Madrid.
Barca, with confidence soaring on the back of a 15-match unbeaten run, were quickly into their stride and probing the Atletico defence for any sign of the weaknesses that had contributed to the Rojiblancos' dismal recent run.
However, apart from a disallowed Eto'o goal and a Gianluca Zambrotta effort that was comfortably saved by Christian Abbiati, there was a dearth of chances in the opening 25 minutes.
In fact, the biggest celebrations during that spell were reserved for news from Recreativo Huelva that leaders Real had gone a goal down - a fact that was warmly received by both Atletico and Barca fans.
It was only the small group of visiting supporters celebrating at the Vicente Calderon just before the hour-mark though, as Ronaldinho produced a moment of magic to put Barca ahead.
Xavi's dinked cross in from the right looked to be too far behind the Brazilian, but Ronaldinho, with his back to goal, flung himself at the ball before sending a spectacular overhead kick past the helpless Abbiati and into the net.
That goal was probably no more than dominant Barca deserved, but the game was to turn on its head before half-time with Atletico stunning the visitors with two quickfire goals.
Top scorer Aguero, who was back in the Atletico side following suspension, got the hosts back on level terms in the 36th minute.
The goal owed a great deal to fortune though, with the Argentinian youngster's effort taking a crucial deflection off Carles Puyol, leaving Barca goalkeeper Victor Valdes totally wrong-footed as the ball flew inside his near post.
Valdes was then beaten again in the 41st minute as Maxi Rodriguez put Javier Aguirre's men ahead.
Aguero was again involved with a clever ball inside the area, and his fellow Argentinian latched onto the pass before drilling a low shot across Valdes and into the far corner of the net.
Aguero had a great chance to make it 3-1 nine minutes into the second half after being put through by Forlan, but he blazed into the side-netting with the Barca defence appealing in vain for offside.
Barca coach Frank Rijkaard sent on his own Argentinian superstar Lionel Messi soon after that in a bid to turn the game back in his side's favour, but it would be Atletico who would get the next goal on the hour.
A clumsy challenge by Barca captain Puyol saw Aguero go sprawling in the box and Diego Forlan stepped up to coolly slot home the resulting penalty.
Puyol escaped with only a yellow card for his foul, but Barca were still left with a massive task to avoid defeat.
Eto'o almost gave the visitors an immediate lifeline but he was denied by a brilliant save by Abbiati following a corner.
The match was rapidly turning into the Aguero show though, and the teenager made it 4-1 in the 71st minute with a fine solo goal.
He showed great determination to rob Puyol of the ball 40 yards out, before skipping past the attempted tackle of Gabriel Milito and then curling an inch-perfect shot inside the far post from outside the area.
That was not the end of the scoring however, and Barca hit back almost immediately to give themselves hope of salvaging a point, with Eto'o firing the ball home after Eidur Gudjohnsen had been denied to make it 4-2.
Barca pushed forward late on in the hope of making further in-roads, but Eto'o was unable to stab in a late chance as Atletico held on for a potentially crucial win - both for them and the title race.
