Barcelona coach Pep Guardiola has told his players they need to lift their game if they hope to catch La Liga leaders Real Madrid and secure a fourth straight Spanish title.

Barca slipped to a shock 1-0 loss at Getafe on Saturday, confirming their poor form away from home, and are six points adrift of Jose Mourinho's Real after 13 matches.

With the great rivals due to meet for the opening 'Clasico' of the campaign on December 10 at Real's Bernabeu stadium, Guardiola conceded the Madrid side had been the more impressive so far this season.

"As a sportsman this is not the first time I see myself trailing a rival," he said ahead of Barca's game at home to Rayo Vallecano on Tuesday, a match brought forward because of Barca's participation in next month's Club World Cup in Japan.

"Real Madrid are six points clear because up to now they have been better than us," Guardiola added.

"We know that Real Madrid are very strong and we know we'll have to lift our game or we won't get there.

"We will try to raise our level because our current one is not good enough to be top of the league.

"We'll try and if we don't succeed we will congratulate our opponent for having been superior."

Barca's form at home has been almost impeccable, with six wins and a draw in seven games and 30 goals scored against none conceded.

However, they have won only two of six away matches, drawing three and losing one, and have managed only eight goals for and seven against.

"At home we are more consistent and away we are finding it harder but we have not been worse than our opponents in a single one of those games," Guardiola said.