A first-half goal from Turkish midfielder Arda Guler secured the win for Madrid, which kept its LaLiga title ambitions alive.

However, the triumph came at a cost and coach Carlo Ancelotti is already without key players Kylian Mbappe and Ferland Mendy ahead of Sunday's (AEST) Copa del Rey final against rival Barcelona.

"We will see what the medical exams say but [Alaba and Camavinga] both suffered leg muscle injuries and it looks very unlikely for them to make it to Saturday's [Sunday's AEST] final," Ancelotti said.

With Mendy, Alaba and Camavinga all potential absentees, Ancelotti may have to rely on Fran Garcia to fill the left-back position, where he would be tasked with keeping Barcelona's 17-year-old sensation Lamine Yamal quiet.

Barcelona, whichis chasing a treble with the first leg of its UEFA Champions League semi-final against Inter Milan next week, sits top of LaLiga on 76 points, four ahead of Madrid with five games remaining.

It has already recorded emphatic victories over Madrid this season, winning 4-0 at Santiago Bernabeu in LaLiga in October and 5-2 in the Spanish Super Cup final in Saudi Arabia in January.

"There may be a favourite, but a final is a final. And anything can happen," Ancelotti said.

"We will have to defend well, but we'll have our chances up top. Today's victory is a good boost. It was a good first half and more difficult at the end, but we won."