London - Rafael Nadal, Roger Federer, Maria Sharapova and Serena Williams lend heavyweight star quality to super Saturday at Wimbledon with places in the fourth round at stake but with torrenatial rain threatening major disruption.
Nadal, the 2008 and 2010 champion, has reached the last 32 for the first time since 2011 and will tackle Kazakhstan's Mikhail Kukushkin.
Two days after taking revenge on Lukas Rosol, the big-hitting Czech who knocked him out in the second round in 2012, Nadal will be fired up after finding himself on the receiving end of barbs over the time he takes between points.
Rosol pointed the finger directly at the Spaniard while Federer joined in with a more subtle appeal to have play in general speeded up to ward off fears that fans could desert the sport if it loses its attractiveness.
Nadal has beaten Kukushkin, the world number 63, in both their previous encounters for the loss of just seven games.
Federer, the seven-time champion, tackles Colombian world number 35 Santiago Giraldo who he defeated in their one previous meeting in straight sets at the 2011 US Open.
Giraldo had never got beyond the second round at Wimbledon until this year.
Sharapova, who won the first of her five majors at Wimbledon as a 17-year-old in 2004, faces America's Alison Riske who she beat on grass in the semi-finals in Birmingham in their only other previous clash in 2010.
"I feel like her game matches up with grass extremely well. She stays down really low, hits really flat from both sides, has had steady results on the surface. It's going to be a challenge. Yeah, I look forward to playing her," said French Open champion Sharapova.
Five-time champion Serena Williams, the top seed, takes on 25th seed Alize Cornet boasting a 3-1 career record but with the Frenchwoman having won their most recent encounter in the Dubai semi-finals this year.
Last year's runner-up Sabine Lisicki faces Serbia's former world number one Ana Ivanovic with Australian Open men's champion Stan Wawrinka, the fifth seed, facing Denis Istomin of Uzbekistan.
Start of play was delayed on the outside courts as heavy rain lashed the All England Club, but the Centre Court programme will remain unaffected as the stadium roof was closed, clearing the way for a 1200GMT start.
A host of sports stars will be in the Royal Box including former England football captain David Beckham and retired Indian cricket legend Sachin Tendulkar.
Bradley Wiggins was also due to take his seat just a day after being dumped from Sky's team for the Tour de France.