Ronaldo, the world's most expensive player, paraded the Golden Boot before kickoff for the 40 league goals he scored last season, and he helped his bid to win it again with a hat trick at the Bernabeu.

Argentina winger Di Maria set up the first three goals for Ronaldo, Pepe and Gonzalo Higuain before being carried off with what looked like a thigh injury at the start of the second half.

Ronaldo notched up his second goal from the penalty spot in the 54th when Osasuna had defender Eneko Satrustegui sent off, and he bagged his fourth league treble this season in the 57th, taking his La Liga tally to 13.

Substitute Karim Benzema wrapped up the scoring with two more goals.

Injury-hit Osasuna, who were thrashed 8-0 away to Barcelona in September, had drawn level at 1-1 in the 31st minute when Ibrahima took advantage of a quickly-taken free kick to beat Iker Casillas.

Real climbed to 28 points from 11 games, four clear of second-placed Barcelona, who can close the gap back to one point with a win at Athletic Bilbao later on Sunday (1900 GMT).

Valencia are third with 24 points after winning the city derby 2-0 at Levante on Saturday, pushing the season's surprise early pace-setters down to fourth with 23 points.

Late Saturday, surprise package Levante suffered a second consecutive La Liga defeat as they lost 2-0 at home to Valencia in a turbo-charged city derby on Saturday.

An own-goal from Javi Venta and free kick from Tino Costa after the break saw Valencia climb above their neighbors into third place on 24 points, just one behind leaders Real Madrid.

Levante are in fourth place a point further back.

"It was the game we expected in terms of intensity, competitiveness and tension," Valencia coach Unai Emery told reporters. "We managed it well against a team who had won every game at home." Sevilla are fifth on 18 points after a drab 0-0 draw at a rain-soaked Real Mallorca, with Marcelino's side still to record a win on the road this season.

Mallorca's new coach Joaquin Caparros remains without a win since replacing Michael Laudrup early last month.

Malaga are sixth on 17 points after being held to a 0-0 draw at Andalucian rivals Real Betis with the big-spending south-coast club continuing to struggle to live up to expectations.

Promoted Betis, who were top of the table six weeks ago, earned their first point in seven outings, ending a run of six defeats in a row, which has seen them plummet to 11th.

It was the first time in nearly half a century that Levante had hosted Valencia while placed higher in the standings.

The tackles flew in hard and fast and the referee flashed five yellow cards before the break as tempers were never far from boiling over.

Tino Costa's clever ball behind the defense set Jordi Alba scampering into the area after 32 minutes, but as Levante fullback Venta slid in to tackle him he diverted the ball past his own keeper.

Costa doubled the lead when home keeper Gustavo Munua completely misjudged the Argentine's freekick after 50 minutes.

Levante lost their first game of the campaign by the same scoreline 2-0 at Osasuna last weekend.

"I have to congratulate Valencia because they played a good game but the goals were hard to take especially the second," Levante coach Juan Ignacio Martinez said.

"We'll pick ourselves up. We have to think about now and not what could have been."