Real Madrid may be without joint La Liga top scorer Cristiano Ronaldo for Sunday's trip to Racing Santander after the Portuguese forward was forced off by a muscle problem in Thursday's 7-0 drubbing of Malaga.
Ronaldo ended a four-match goal drought with a hat-trick at the Bernabeu but had to leave the pitch with just over 10 minutes remaining, reducing Real to 10 men as they had used all three of their substitutes.
Jose Mourinho's side were already seven goals ahead and their biggest win of the season cut Barcelona's lead at the top back to seven points with 26 matches played after Lionel Messi had given the champions a 1-0 win at Valencia on Wednesday.
"I did it when I scored the third goal but I am sure it's nothing special," Ronaldo, level with Messi at the top of the La Liga scoring chart on 27 goals, told reporters.
"It's better not to take risks. I don't think I'll be available for Sunday's match."
The game at the Sardinero (2000 GMT) is a chance for Racing's new Indian owner Ahsan Ali Syed to see first hand how his team fares against one of La Liga's two dominant clubs.
Ali Syed, the chairman of investment company Western Gulf Advisory who became Racing's majority shareholder at the end of January, told Reuters last month he aims to make the club a "third force" in Spain alongside Real and Barca, who host struggling Real Zaragoza on Saturday (1900).
Racing, in 12th on 30 points, five above the relegation places, are undefeated in six matches since Ali Syed's arrival.
New coach Marcelino Garcia, who replaced the sacked Miguel Angel Portugal on Feb. 9, appears to be more focused for the time being on securing their place in the top flight than challenging the world's top two richest clubs.
"A win would be an important step, not a definitive one, to make sure of our survival," he told a news conference on Wednesday.
"The match will be tough, although thanks to the points we already have it will be more important for them.
"Their need could be a virtue but the longer the match goes on the more anxious they might get and that could help us."
Third-placed Valencia, who are 13 points behind Real, play at Real Mallorca on Saturday (1700), while Villarreal, a point back in fourth, are at eighth-placed Atletico Madrid in Saturday's late kickoff (2100).
Barcelona coach Pep Guardiola may not be able to attend Saturday's match against Zaragoza after suffering a spinal disc hernia on Thursday.