Ronaldo scored in the 3-0 win which saw the five-times world champions come top of the South American group after Argentina's loss to Uruguay but complained of pain in his quadriceps muscles as he reported back for Real training.

Real were set to give him a fitness test Friday morning to determine if he would be ready potentially to fire Real to the top of the table after the club's recent resurgence in La Liga.

The club are currently third, two points behind surprise early leaders Getafe while Atletico are in mid-table.

Ronaldo has scored five goals already in six games of the Liga for Real and finished top-scorer in the South American qualifiers with 10. The man dubbed the 'phenomenon' was also in the short-list of 30 announced by FIFA on Thursday for the World Player of the Year award, a laurel he has already bagged a record three times along with Real Madrid mate Zinedine Zidane.

Real's derbies with Barcelona are watched around the world but the battles between Real and Atletico have almost the same global appeal. And the clash at Atletico's Vicente Calderon stadium comes with both teams having something to prove.

Real would want to continue their good run after a shaky start to the season and notch up their fourth consecutive league victory.

"We're on a winning streak at the moment so we want it to continue," said Real playmaker Jose Maria 'Guti' Gutierrez on Thursday.

"In the last few years, whether we've played well or badly, we always seem to come away from the Calderon with something," added the player whose continued absence from the the Spanish national team remains a mystery to many.

By contrast, Atletico hauled themsleves out of the relegation zone after their 2-0 win at Malaga two weeks ago and coach Carlos Bianchi is keen to prove that his team have the credentials to continue their rise and challenge for a place in Europe.

"In a derby, there isn't any favourites, regardless of where it is played," said Atletico striker Maxi Rodriguez.

"The key to beating Real is not to let them have any space. They have fast and clever players, if we give them a metre or two then we are going to suffer," added Rodriguez, who will be joined up front by former Chelsea striker Mateja Kezman.

Kezman is rapidly establishing himself as the deadliest striker in Spanish club football after Ronaldo.

The Serb added to his reputation on Wednesday with the only goal in Serbia and Montenegro's 1-0 win over Bosnia which sealed his country's automatic qualification for next summer's World Cup finals.

David Beckham will also be in Germany but his joy at England qualifying was tempered by Real's midweek demand that he return to Spain to train as he was suspended for the match against Poland.

England won 2-1 despite their captain's absence and Beckham is known to have been unhappy at Real's attitutde as he wanted to be in the stands supporting his international colleagues.

Like Real and Atletico, most Spanish first division clubs were eagerly awaiting the return of their top players on Thursday, following the World Cup fixtures of the last week, to take stock of the bumps and bruises.

However, Madrid's third top flight club, the surprise league leaders Getafe had no such worries as the unbeaten side from the southern suburbs of the Spanish capital had no one in international action.

Getafe go to Real Betis on Sunday with their first choice midfielder Fabio Celestini sidelined for at least another week with a slight muscle tear in his left thigh.

Second-placed Celta Vigo have a tricky trip to Osasuna on Sunday.

Reigning Spanish champions Barcelona, who are currently fifth, travel to Deportivo la Coruna Saturday with the Catalan club's striker Samuel Eto'o vowing to redeem himself after Cameroon's World Cup failure last weekend.

"I have been to two World Cups and I would have loved to have gone to a third, it's the biggest celebration of football in the world so I'll have to make up for missing out with some club achievements," said Eto'o.

FIXTURES
Saturday (kick off times in GMT): Alaves v Villarreal (1600), Deportivo La Coruna v Barcelona (1800), Atletico Madrid v Real Madrid (2000)
Sunday: Real Betis v Getafe (1500), Real Zaragoza v Real Sociedad (1500), Real Mallorca v Racing Santander (1500), Osasuna v Celta Vigo (1500), Valencia v Malaga (1700), Espanyol v Cadiz (1700), Athletic Bilbao v Sevilla (1900)