Faltering La Liga champions Real Madrid slid to a shock 2-1 home defeat by Alaves on Saturday as goalkeeper Thibaut Courtois made a catastrophic error and record signing Eden Hazard suffered yet another injury.

Lucas Perez gave Alaves the lead in the fifth minute from the penalty spot after a handball from Nacho, the fifth penalty that Madrid have conceded in the league in three matches.

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Hazard wasted a chance to equalise when he fired straight at Alaves keeper Fernando Pacheco and then had a penalty appeal waved away before hobbling off with a muscle injury in the 28th minute.

Former Madrid youth player Joselu made the most of a gift from Courtois to double Alaves's lead early in the second half, unexpectedly receiving a stray pass from the Belgian outside the area and slotting into the empty net.

Casemiro pulled back a goal for Madrid in the 86th minute from close range while Isco almost found an equaliser in the sixth minute of added time but his shot bounced off the crossbar and Madrid had to swallow a third defeat in 10 league games.

Zinedine Zidane's side are fourth in the standings on 17 points after 10 games, six below leaders Real Sociedad and second-placed Atletico Madrid. Alaves climbed up to ninth on 13.

"Alaves made a much better start than us and if you don't score you pay for it as this is the toughest league in the world and every opponent has quality," Real midfielder Casemiro said.

"This is a very different season from most, all the big teams are dropping points but we have to keep working and try to do better. At least we kept trying until the end today.

"Our pre-season campaign was not good and we have almost no time to work because there are so many games. But we need to keep on fighting as there's still a long way to go."

Madrid were lifted by a commanding 2-0 victory away to Inter Milan in the Champions League on Wednesday but were still missing six players, including captain Sergio Ramos and striker Karim Benzema, their two top scorers last season.

Zidane decided to rotate first-choice left back Ferland Mendy and give another chance to veteran Marcelo, who struggled in the 4-1 defeat by Valencia three weeks ago.

But the move backfired yet again as Real suffered their 10th league defeat since Zidane returned to the club in March 2019.