LONDON // Wimbledon began with questions being asked about how durable the dual dominance of Rafael Nadal and Roger Federer would prove to be, and how much longer the sister act of Serena and Venus Williams would reign supreme over the rest of the world's best women. A fortnight later those questions appear to be half answered. Federer and Venus Williams can no longer claim to be king and queen of the Centre Court, despite being crowned there on six and five occasions, respectively.
Nadal and Serena Williams, however, look more powerful than ever. Providing that these two world No 1s remain fit and committed - and they are big provisos because Nadal is plagued by injury doubts and Williams is frequently distracted by off-court interests - they both seem destined for places among the greatest in the game. Federer is now universally acknowledged as the finest men's player ever, having completed a career Grand Slam last year and gone on to establish his cherished record of 16 major titles. Now, however, he now seems powerless to restrict Nadal in the Spaniard's relentless pursuit of further accolades. The manner of Federer's comprehensive defeat by Tomas Berdych in the quarter-finals of his favourite tournament, and the way he succumbed to Robin Soderling at the same stage of the French Open, suggests that the Swiss maestro's best days are now behind him.
Federer is now down to No 3 in the ATP rankings, the first time since 2003 that he has been outside the top two, although it would be foolish to disregard him for the US Open, which is only seven weeks away. Similar dismissive comments were being made about Nadal a year ago after he, too, was denied victory at Roland Garros by Soderling, and then failed to appear to defend his hard-earned first Wimbledon title because of chronic knee tendinitis.
Those who chose to write off Nadal as a spent force when he was only 23 were justified at the time in making those observations. How foolish those comments look now, though, as Nadal danced around for two mesmerising weeks in a grass-court environment that was once alien to him. The ruthless way the Spaniard dealt with a terrific challenge from Britain's Andy Murray was the highlight of the tournament for most purists. If Murray continues to improve - the British No 1 is still only 23 - he can get closer to Nadal. It was Federer, however, who nominated the man who could prove to be the most serious threat to Nadal. Federer is a big fan of Juan Martin del Potro, the tall Argentine who beat him last year in the US Open final, but he will not be fit enough to defend that honour because of a wrist injury.
If Del Potro does what Nadal has done and returns healthier and stronger from his career-threatening fitness problems, then he may stop Nadal from mopping up of the most sought-after prizes. The record total for women's singles grand slam titles stands at a remarkable 24 established when the Australian Margaret Court won the US Open for the fifth time in 1973. Serena Williams has the ability and physical strength to challenge that, but at 28 and with interests elsewhere, it is doubtful she will have the hunger to pursue it. One woman who fleetingly looked like she could stop the American juggernaut at Wimbledon was Maria Sharapova, who did just that in the 2004 final, and looks to be getting back to her best after having corrective surgery on her shoulder.
It was a pity the Russian was in the same section of the draw as Williams. Their fourth-round encounter, which hinged on her failure to take set points in a pivotal first-set tie-breaker, was probably the best match of the women's tournament - better than the intriguing all-Belgian clash between the "comeback queens" Kim Clijsters and Justine Henin, which was played on the same day. Henin injured her elbow on the way to defeat in that match and will not be fit to take her place alongside the champion Clijsters at Flushing Meadows. The injury will also prevent her from playing in Brussels on Thursday, in front of what has been billed as the largest crowd for a tennis match. Henin was scheduled to take on Clijsters in an exhibition which has generated more ticket sales than the "Battle of the Sexes" match between Billie Jean King and Bobby Riggs 37 years ago. But, the 40,000-seat show must go on, though, and who better to put on the other side of the net to Clijsters than Serena Williams?
1. Rafael Nadal (ESP) 10,745 2. Novak Djokovic (SRB) 6,905 3. Roger Federer (SUI) 6,885 4. Andy Murray (GBR) 5,155 5. Robin Soderling (SWE) 4,935 6. Nikolay Davydenko (RUS) 4,740 7. JM del Potro (ARG) 4,350 8. Tomas Berdych (CZE) 3,845 9. Andy Roddick (USA) 3,490 10. Fernando Verdasco (ESP) 3,475
1. Serena Williams (USA) 8,475 2. Jelena Jankovic (SRB) 5,900 3. Caroline Wozniacki (DEN) 5,630 4. Venus Williams (USA) 5,606 5. Samantha Stosur (AUS) 4,890 6. Elena Dementieva (RUS) 4,670 7. Kim Clijsters (BEL) 4,510 8. Francesca Schiavone (ITA) 4,425 9. Vera Zvonareva (RUS) 3,965 10. Li Na (CHI) 3,756