Barcelona surged into the Spanish Primera Liga title race on Sunday after they claimed a dramatic 2-1 win at arch-rivals Real Madrid while leaders Valencia were held to a 1-1 draw at Athletic Bilbao.
Valencia moved a point ahead of Real at the top of the table, but Barca are now only four points behind last season's champions in third.
With four games left, Valencia have 71 points, Real follow on 70, while Barca have 66, four ahead of Deportivo Coruna, who were held to a 1-1 draw at Malaga on Saturday, and 14 clear of fifth-placed Athletic Bilbao.
Real took the lead through midfielder Santiago Solari after an intense period of pressure early in the second half, but Barca equalised four minutes later when substitute Patrick Kluivert headed in from close range.
The sending off of Real midfielder Luis Figo midway through the second half gave his former side the upper hand and Xavi scored a brilliantly worked winner four minutes from time to ensure Barca of their first league victory at the Bernabeu in over six years.
Aware of Real's defeat, Valencia got off to a perfect start against Athletic when midfielder Jorge Lopez scored from the penalty spot in the 12th minute.
But Athletic, who are bidding for a place in next season's UEFA Cup, fought back well and equalised on the half hour when defender Asier del Horno rose above a forest of Valencia players to head in a Fran Yeste free kick.
AGGRESSIVE START
Stung by criticism of their recent performances champions Real made an aggressive start in front of their home fans.
But the Catalans responded well and put together neat passing moves as Xavi and Ronaldinho orchestrated affairs in midfield.
It was Barca goalkeeper Victor Valdes, though, who proved to be his side's hero when he produced a string of near-miraculous saves as Real laid siege to the Barca goal in the final 10 minutes of the first half.
The young keeper pulled off a fantastic double stop as he parried a low shot from Zinedine Zidane, then blocked the follow-up from Raul, while defender Carles Puyol somehow managed to clear a rasping drive from Roberto Carlos off the line after the ball had bounced back into play.
Valdes came to the rescue once again two minutes later, this time beating away a swerving free kick from David Beckham, then blocking a Raul shot before producing an amazing one-handed save to scoop a goal-bound Figo header off the line.
Real refused to let their opponents off the hook and went close on several more occasions, Figo hitting the side netting just before the break and Beckham smashing wide soon after the re-start.
Valdes was pressed into action a minute later when he turned a trademark rocket-shot from Roberto Carlos over the bar and produced another great double save to block rasping shots from Zidane and Figo.
But he was unable to stop Real from taking the lead in the 54th minute when Solari drilled low inside the far post after the Barca defence failed to clear the resulting corner.
Barca coach Frank Rijkaard immediately decided to ring the changes, bringing on Dutch striker Kluivert and former Real forward Luis Enrique.
His gamble paid off within a minute as Kluivert headed home the equaliser after Giovanni van Bronckhorst got behind the Real defence and clipped a cross over the advancing Casillas.
Real received another setback 11 minutes later when Figo was dismissed after picking up his second booking of the game for a challenge on Puyol and it was Barca who then took control.
Frank Rijkaard's side sealed victory seven minutes later when Ronaldinho chipped a delicate pass over the exhausted Real defence and Xavi hooked the ball over the advancing Iker Casillas into the net.
