As the Williams sisters begin to dream of another year of Wimbledon glory, they would be wise not to underestimate the challenge from comeback kids Justine Henin and Kim Clijsters.
Venus and Serena have made the Rosewater Dish, awarded to the women's singles champion at Wimbledon, their personal property for much of the last decade. Their remarkable run at the All England Club began with Venus's victory over Lindsay Davenport in 2000 and the American retaining the title a year later before Serena took over -- beating her sister in two successive finals.
That set the pattern for the rest of the decade as Venus took the singles crown a total of five times, while Serena's final victory in 2009 -- inevitably over her sister -- was her third Wimbledon success.
Only in 2004, when Maria Sharapova came from nowhere to shock Serena in the final, and 2006, the year Amelie Mauresmo took the title, has there been a non-Williams winner in the last 10 years.
With Serena established as the world number one heading into this year's Wimbledon, which starts on Monday, and Venus just one place behind her in the rankings, it would be no surprise if the sisters carve their way through the field again.
Few players can match their combination of power and poise on the grass courts in south-west London, but the re-emergence of Henin and Clijsters could offer a glimmer of hope for those who would like a little more unpredictability in the women's event.
Henin was the world number one when she surprisingly retired from tennis in 2008. The Belgian had been badly affected by the break-up of her marriage a year earlier and opted to quit to concentrate on her personal life. It was a decision which gave her peace of mind off the court but she missed the adrenaline rush of top-level competition and returned to the tour for the start of 2010.
Playing as a wildcard at the Australian Open, Henin showed she had lost none of her ability as she knocked out a string of seeds on route to the final. A gutsy display against Serena in the final ended in a three-set defeat but Henin had proved she was going to be a force to be reckoned with again.
With Wimbledon final defeats in 2001 and 2006 on her CV, Henin, a former Australian, French and US Open champion, admits she would love to fill the one gap in her trophy cabinet. "The comeback is not all about Wimbledon but it's a big part of it. Wimbledon is the one I never won and it's going to be my challenge now and I'll never give up," said Henin, who has clinched grand slam victories over both Williams sisters in the past.
Henin's return came soon after her compatriot Clijsters won the US Open just months into her own comeback. Clijsters had retired in May 2007 but, like Henin, she missed the cut and thrust of tennis and decided to get back in action two years later. Defeating Venus in the fourth round of the US Open showed Clijsters had lost none of her gritty game and she followed that shock win by eliminating Serena in the semi-finals before beating Caroline Wozniacki in the final.
Clijsters missed this year's French Open due to a foot injury but she returned to action at Eastbourne this week and is already eyeing another shock run to a grand slam title. Clearly, the Williams' have been warned.