Atletico Madrid will be hoping a spate of positive COVID-19 tests in their squad does not derail their La Liga title charge when they welcome Celta Vigo on Monday.
They have a 10-point advantage at the top of the table but will be without four first team players due to COVID-19.
Joao Felix, Mario Hermoso, Yannick Carrasco and Moussa Dembele are isolating and miss the trip to Galicia in a crisis that will test the depth of coach Diego Simeone's squad.
Simeone said last week he had been philosophical whenever faced with COVID absentees this season.
"We just have to live with these kind of situations when they come our way. We're moving forwards knowing it's something that we'll just have to deal with all season," he said.
Victory would be Atleti's 10th in a row in La Liga, and they are on course to beat their highest-ever points tally of 90, having accrued 50 from their opening 19 games.
Barcelona now lead the chasing pack, level on 40 points with Real Madrid, and are in their best form since coach Ronald Koeman took over in the close season.
The Catalans, who visit Real Betis on Sunday, are on a 10-game unbeaten league run which started in December.
They also scraped into the Copa del Rey semi-finals with an 5-3 extra-time victory over Granada on Wednesday.
"These kind of games, getting through like this helps, you gain strength," Koeman said.
"We've shown that despite a lot of things going against us, we are on the right track and these are important things for our season."
Third-placed Real Madrid travel to bottom side Huesca on Saturday looking to recover from last weekend's shock 2-1 home defeat by mid-table Levante.
They welcome back captain Sergio Ramos, who has missed the last three games, for the trip north but Eden Hazard misses out with a thigh problem.
(Reporting by Joseph Walker; Editing by Ken Ferris)
