Real Madrid defender David Alaba will be sidelined for months after suffering a severe knee injury in his team's 4-1 win over Villarreal on Sunday in La Liga.

The Austrian centre-back went off hurt in the first half after attempting to challenge Villarreal forward Gerard Moreno.

"After the tests carried out on our player David Alaba, he has been diagnosed with a rupture of the anterior cruciate ligament in his left knee," said Madrid in a statement.

"The player will undergo surgery in the coming days."

Alaba's injury adds to cruciate ligament injuries for goalkeeper Thibaut Courtois and defender Eder Militao, while midfielder Eduardo Camavinga is also sidelined with a knee ligament rupture.

Madrid have only two fit central defenders, in Antonio Rudiger and Nacho Fernandez.

Midfielder Aurelien Tchouameni returned from injury as a substitute against Villarreal and could be chosen to cover in defence by coach Carlo Ancelotti.

"It's a shame, it's very sad, and I've never had three cruciate ligament (problems) in four months," Ancelotti told reporters after Alaba's injury.

"We have carried that and done more than what people thought."

Madrid are also without star forward Vinicius Junior, who has a hamstring injury, but Jude Bellingham, Rodrygo Goes and Brahim Diaz have helped fill in for the Brazilian.

All three scored along with Luka Modric in Madrid's convincing win over Villarreal.