Lionel Messi came off the bench to help Barcelona come from behind to beat Racing Santander 2-1 with two classy late goals in a match that also saw the winners ending with nine men.
Messi's goals led Barca to their ninth straight league win Sunday and left them with a record-breaking 56 points from 21 games, 12 more than second-placed Real Madrid, who won 2-0 on Saturday at Numancia.
Barca coach Josep Guardiola raised eyebrows by leaving the in-form Messi on the bench. His team sorely missed the creativity of the Argentine and failed to produce a clear chance throughout the first half.
Eleven minutes into the second half, Santander were given a penalty for a foul by Rafa Marquez on little Jonathan Pereira, and Nikola Zigic made no mistake from the spot.
Guardiola brought on Messi, and suddenly Barca were a team transformed.
In the 66th minute, Xavi headed a Thierry Henry centre onto the crossbar, and Messi followed up to put away the rebound, making it 1-1.
Fourteen minutes later, Messi made it 2-1 with a powerful drive with his supposedly weaker right foot, after Samuel Eto'o had opened up the Santander defence.
Barca had defenders Marquez and Gerard Pique sent off at the end, but even so had few problems in holding on for their ninth win.
"They are an excellent side," said Santander veteran Munitis, "and it would be a massive shock to everyone if they did not win the league."
Real Madrid are six points ahead of third-place Sevilla, who lost 1-0 at Sporting Gijon in Sunday's late game.
Sevilla keeper Andres Palop saved an early penalty from Mate Bilic but failed to keep out an 18th-minute header from Diego Castro - the only goal of an open match.
Gijon played with 10 men for more than an hour, due to the sending-off of left-back Roberto Canella. Sevilla dominated from then on, but lacked penetration in attack.
In fourth place, one point behind Sevilla, are Valencia, who beat spirited Almeria 3-2 with two goals from Euro 2008 top scorer David Villa.
Injured for two weeks, Villa was sorely missed in Thursday's cup defeat at Sevilla.
Joaquin volleyed Valencia ahead after just six minutes, only for Alvaro Negredo to quickly level for Almeria. Villa restored Valencia's lead on the half hour from the penalty spot, after Juan Mata had been pulled down.
Villa made it 3-1 with his left foot in the 62nd minute. The game seemed over, but Negredo straight away took advantage again of the brittle Valencia defence to make it 3-2.
Almeria deserved to force a draw at the end, with Mestalla desperate to hear the final whistle.
Valencia are now three points ahead of fifth-place Villarreal, who crashed 3-0 at Deportivo Coruna. Star of the show in La Coruna was Angel Lafita, who scored for the hosts in the third and 62nd minutes.
The handsome win takes Deportivo up to sixth, just one point behind Villarreal and Valencia.
Atletico Madrid stay seventh, one point behind Deportivo, after crashing 2-1 at home to lively Valladolid.
Luis Prieto gave Valladolid the lead six minutes into the second half. Five minutes later, a clumsy own goal from Jose Garcia Calvo made it 1-1.
But Valladolid were looking much brighter than nervous Atletico, and veteran Victor hit the winner from the penalty spot 11 minutes from time, after Mariano Pernia had pulled down Henok Goitom. The game finished with long-suffering Atletico fans chanting for the sacking of coach Javier Aguirre.
Sunday's other early games all had relegation significance.
Osasuna beat Mallorca 1-0, Espanyol drew 1-1 with Recreativo Huelva, and Betis were held 2-2 by Getafe.
Mallorca, Espanyol and Osasuna are now tied at the bottom, all on 17 points, with Numancia three points above them and Betis five points clear.