Tennis: Big Four semifinal on the cards

Serena Williams returns from nearly a year's absence from tennis. Roger Federer (left) has not lost a set so far. Photo / AP

We expected Roger Federer, Rafael Nadal, Novak Djokovic and Andy Murray to cruise through week one, but who has impressed most out of the Big Four?

When Federer, Nadal, Djokovic and Murray reached the semi-finals of the French Open this month it was the first time the top four seeds had made the last four of a Grand Slam event for five years.

Do not be surprised if it happens again this week.

Neither Federer nor Nadal have lost a set yet. Djokovic has dropped one and Murray two, but none of the Big Four have looked in any serious trouble. The seeding system has ensured they have not faced any major challenges yet, but all that changes today. Nadal (against Juan Martin del Potro) and Murray (against Richard Gasquet) face especially challenging fourth-round tasks.

Nobody has looked in better shape than Federer. Questions were asked about his grass-court preparation when he pulled out of his warm-up tournament at Halle, but the Swiss has won the title here before without any competitive matches under his belt and has immediately settled back into a rhythm. When you have won this title six times it does not take long to become accustomed to the feel of grass under your feet.

David Nalbandian, who for many years had won more matches against Federer than he had lost, was swept aside on Saturday by the Swiss, whose serve has particularly caught the eye.

Nevertheless, in most recent Grand Slam tournaments Federer has tended to coast through the early stages but falter when he comes up against the very best. If he is to win the title here, he might have to beat Djokovic and Nadal in successive matches.

Nadal usually takes longer to adapt to grass and has done so again this year. There were times against Gilles Mller on Saturday when he looked far from comfortable. However, the Spaniard is now on a 17-match winning streak at the All England Club and since 2005 has lost just twice here, to Federer in the 2006 and 2007 finals. Expect the world No 1 to improve as the week progresses, though he will need to be on his mettle against Del Potro today.

Djokovic has been phenomenal in the first six months of this year and has looked in good nick here, apart from the second set he lost against Marcos Baghdatis. He has not been at his best on grass in the past but has played beautifully so far. His ball-striking is sweeter than it has ever been and there is unmistakable air of confidence about him.

Murray has mixed the magical with the occasionally moderate. At his best he has been excellent, upsetting opponents with his lightning changes of pace, skidding slices, hammer-blow backhands and crafty lobs and drop-shots. However, there have been times when his level has dipped. In particular, his second serve has sometimes been exposed: he cannot always rely on his ability as one of the best returners in the business.

Who else has quietly caught the eye in the men's draw?

Tomas Berdych, last year's runner-up, has again been flying under the radar. The Czech has won a remarkable 89 per cent of his points when his first serve has found the target. If he maintains that consistency he will be hard to beat. Del Potro has also been striking the ball with formidable power, though he faces the ultimate test today against Nadal. Jo-Wilfried Tsonga has been as entertaining as ever and could test Federer in the quarter-finals.

There is no greater emerging talent than Bernard Tomic, a former junior world No 1 who has a lovely languid style, hits the ball beautifully and has a big-match temperament. The 18-year-old Australian, who followed up his victories over Nikolay Davydenko and Igor Andreev by knocking out Robin Soderling on Saturday, has the look of a future Grand Slam champion.

How can Serena Williams play so well after being out for nearly a year? Can anyone stop her?

You can look at Williams' habit of rediscovering her form so quickly after lengthy absences in two ways. First, it says much about the comparative lack of talent in the women's game; you could not imagine a man making such an instant impact after nearly a year out of the game.

Nevertheless, the former world No 1 is an extraordinary player, one of the best ever to play the game. Not only does she hit the ball with phenomenal power but she is also the most ferocious of competitors. No woman can turn matches around as consistently as the American does.

Marion Bartoli, fresh from her run to the semi-finals in Paris and her victory in Eastbourne, could stretch Williams today, though an even more formidable challenge looms in the semi-finals. Maria Sharapova, the 2004 champion, is playing her best tennis since shoulder surgery disrupted her career and is looking good to claim her first Grand Slam title for more than three years.

What about Caroline Wozniacki, the world No 1?

The return of the Williams sisters has deflected the attention from Wozniacki, who usually spends the early rounds of tournaments answering questions about whether she deserves to be world No 1 when she has never won a Grand Slam title. The Dane has won her first three matches without dropping a set, should beat Dominika Cibulkova today and could then face Sharapova in the quarter-finals.

Although Wozniacki lacks the big shots of some of her rivals, there is no better athlete among the leading women. If the likes of Sharapova or the Williams sisters show any signs of weakness, she can exploit them.

How big a factor has the Centre Court roof been and could it play a significant role in the next week?

If the value of the roof was questionable during the last two Wimbledons, it has come into its own this year and has played a part in ensuring the tournament goes into the second week largely on schedule. Playing under the roof changes the playing conditions; it removes the variables - wind, rain, light, temperature - and increases the humidity, making the balls heavier.

Playing under the roof could favour less experienced players who have not played as much on grass. It could also favour Murray, who has now played under the roof three times. Nadal, for example, has never played under it.

- Independent