Manchester United manager Louis van Gaal confirmed Sunday that he would be interested in bringing Cristiano Ronaldo back to Old Trafford, six years after the superstar left for Real Madrid.

Van Gaal, quoted by several British Sunday newspapers, said: "We are looking at all players, not just Ronaldo. But these players are mostly ungettable.

Barcelona took a huge step towards retaining their La Liga title by moving six points clear at the top with a 4-0 thrashing of Real Madrid on Saturday.

Here, AFP Sports looks at what can be learned from a bleak evening for Madrid boss Rafael Benitez.

Jose Mourinho hopes Diego Costa's winning goal against Norwich City will prove to be a turning point for the Chelsea striker.

The Spain forward has come in for growing criticism after struggling to recapture the form he showed during his club's march to the Premier League title last season.

Liverpool manager Jurgen Klopp hopes that his side's brilliant 4-1 dismantling of former Premier League leaders Manchester City will convince his players that they can surmount any obstacle.

Roberto Firmino scored his first Liverpool goal and set up two more as the visitors surged to a 3-0 lead inside the first 32 minutes at the Etihad Stadium on Saturday, with Martin Skrtel rubber-stamping victory late on after Sergio Aguero had reduced the deficit shortly before half-time.

Arsene Wenger described Arsenal's 2-1 defeat at West Bromwich Albion as the "perfect nightmare" after midfielders Francis Coquelin and Mikel Arteta added to his injury problems.

Arteta's own goal, coupled with a late penalty miss by Santi Cazorla, ended the Gunners' six-match unbeaten Premier League run and dented their title challenge.

Novak Djokovic will face Roger Federer in Sunday's World Tour Final when he attempts to lift the trophy for a fifth time and become the first player to win the season-ending showpiece four years in a row.

Djokovic said clashes between the pair were always nervy affairs as he prepared to face his rival for a second time at London's O2 Arena this week -- Federer having got the better of the Serb in the group stage.

Real Madrid head into Saturday's blockbuster clash with Barcelona on the verge of crisis and in need of the world's two most expensive players, Cristiano Ronaldo and Gareth Bale, to prove their worth.

Madrid trail Barcelona by three points at the top of La Liga as their "Galacticos" have failed to fire, while Barca have hardly skipped a beat despite losing four-time World Player of the Year Lionel Messi to injury for the past two months.

Champions Juventus host AC Milan in a potentially high-risk fixture on Saturday that could pit Gianluigi Buffon against the teenage sensation widely expected to succeed him as goalkeeper of Italy.

Juventus appear to have put their disastrous start to the campaign behind them but a stubborn nine-point deficit to leaders Fiorentina means they have plenty of ground to make up in the race for the “scudetto”.

Real Madrid host Barcelona in the 231st meeting between the Spanish giants at the Santiago Bernabeu on Saturday.

Here, AFP Sports looks at five key duels that could decide the outcome in the Spanish capital:

From Manchester United's “Fergie Time” triumphs to Sergio Aguero's 94th-minute title-clinching goal for Manchester City, England's Premier League has long been synonymous with dramatic comebacks. But that may be changing.

As teams become more robust defensively due to more sophisticated tactical preparation and higher levels of physical fitness, so they are becoming better equipped at protecting leads.