Real Madrid's preparations for next week's Champions League semi-final clash against Juventus, as well as their assault on a 29th Spanish league crown, suffered an embarrassing setback on Saturday when they crashed to a 5-1 home defeat to Mallorca.

It was the European champions' first defeat at their Santiago Bernebau stadium since November 2000 and, to add insult to injury, it was Mallorca who inflicted that loss - 49 matches ago.

Later, Real Sociedad cut Madrid's lead at the top to just one point when midfielder Xabi Alonso scored in the 31st minute in their 10 win over Sevilla.

"It is really sad to have lost like this," said Real Madrid's Brazilian defender Roberto Carlos who scored an own-goal in the game at the Bernebau.

"It's also a pity that we lost our home record in such a way but they made things very difficult for us in

the second half.

"But now it's important that we don't let this affect us for Tuesday's match against Juventus because it is the Champions League and we must give it everything we have."

The Real Madrid players were booed off by their fans after the defeat, the club's heaviest since a 5-1 loss to Real Zaragosa in 1999 which led then to the dismissal of former coach John Toshack.

"We had a very bad day," admitted Real coach Vicente del Bosque.

"But we are still the league leaders and we are in the semi-final of the Champions League. We will take stock at the end of the season."

Real dominated large parts of the first half and even opened the scoring in the ninth minute when Brazilian World Cup winner Ronaldo netted his 300th career goal and 17th in the league this season. His effort came after Mallorca keeper Leo Franco failed to stop a drive from Steve McManaman.

But Mallorca, still chasing a UEFA Cup place next season, launched an incredible fightback after the interval, inspired by former Madrid player Samuel Eto'o.

The Cameroon international first set up the equaliser for Walter Pandiani in the 47th minute before they took the lead five minutes later with Eto'o again involved.

He set off on a 40 metre sprint before passing to Alberto Riera to score past Iker Casillas.

It was 3-1 after 63 minutes with the Cameroon ace getting on the scoresheet with a shot from the right before Roberto Carlos put through his own net in the 73rd minute.

Dominguez Carlos added the fifth against a dispirited Madrid in the final minute.