Rafael Nadal faces a fight to hold on to his world number one ranking after Novak Djokovic extended his victory streak to 34 matches with a 7-5, 6-4 win over the Spaniard at the Madrid Masters on Sunday.

Nadal had to swallow his first loss on clay in nearly two years, a run of 37 straight victories stretching back to the French Open fourth round in 2009 when he lost to Robin Soderling.

Football's ruling body FIFA is investigating claims that over 300 matches on three continents were influenced by match-fixers, according to The Daily Telegraph on Friday.

FIFA suspects match officials were paid as little as $10,000 to help engineer specific results in international friendly matches and European club games, netting fixers hundreds of millions of dollars on Asian betting markets.

Barcelona reached their second Champions League final in three years after a 1-1 draw with Real Madrid at the Nou Camp in their semi-final second leg clash here on Tuesday saw them progress 3-1 on aggregate.

Barcelona could now face Manchester United in a repeat of the 2009 final - which Barcelona won - as they hold a 2-0 lead over Schalke going into Wednesday's second leg in Manchester.

Celtic have the chance to take the initiative in the title race if they can claim a win away to Inverness Caledonian Thistle on Wednesday.

Victory would take Celtic back to the top of the Scottish Premier League and two points clear of bitter rivals and defending champions Rangers.

Barcelona coach Pep Guardiola says his team's weekend defeat by Real Sociedad was a timely warning ahead of Tuesday's second leg of their Champions League semi-final with Real Madrid, who they lead 2-0.

Last week they came out on top in a stormy first leg in Madrid that was characterized more by cynical challenges and play-acting than on-pitch excitement.

Rudi Garcia was in defiant mood as Marseille went top of the table for the first time in five months Wednesday, but the Lille handler knows there is little room for error if they are to stun the French champions to take the title.

"It was always going to be likely they went top, but what counts now is how we react," Garcia said after Marseille claimed a 4-2 win against Nice to push Lille into second by one point.

Barcelona is considering a formal complaint to UEFA over accusations by Real Madrid coach Jose Mourinho that referees always favored Barca after his club was defeated 2-0 in the Champions league semi-final first leg.

A late brace from Lionel Messi helped the Catalan giants put one leg in the Wembley final but there were sour grapes as Mourinho, who was sent to the stands at the Bernabeu stadium, vented his fury at the straight red card for Pepe.

The deadline to apply for the 6.6 million tickets available to the public for London's 2012 Olympic Games was Tuesday extended by an hour after the official website crashed due to high demand.

The website froze an hour before the six-week window to apply for tickets was due to close as demand "hit the roof".

Jose Mourinho may be chasing Champions League glory with Real Madrid, but his influence will be felt in the Europa League on Thursday when former club Porto tackle Villarreal in the semi-finals.

Porto have already wrapped up the Portuguese title, leading Benfica by 19 points and yet to lose a league game.

Barcelona midfielder Andres Iniesta is already dreaming of a Champions League final tussle at Wembley even as his side prepared for their semi-final against old rivals Real Madrid.

"I am dreaming of going out there at Wembley. We must think only of going over (to Madrid for Wednesday's first leg) and scoring some goals and then in the return our fans will drive us on to Wembley," Iniesta told a news conference.