WIMBLEDON, England — About 18 months removed from his last Grand Slam championship, Roger Federer figures it's about time for another — his record-tying seventh at Wimbledon.
Despite nearly a year away from the game because of a series of health scares, Serena Williams warns that she "wouldn't bet against" herself.
And even though he's yet to drop a set through three matches — something he'd never managed to do at the All England Club — Rafael Nadal keeps talking up his opponent's chances.
As the 125th edition of the grass-court Grand Slam tournament heads into Week 2, all of the principal players are still around, as are the story lines that drew interest at the start, from the Williams sisters' comebacks to the dominance of the leading men.
After Sunday's traditional day of rest at Wimbledon, action resumes Monday with all 16 men's and women's fourth-round matches. Two stand out in particular: Top-seeded Nadal faces No. 24 Juan Martin del Potro of Argentina, while No. 23 Venus Williams faces No. 32 Tsvetana Pironkova in a rematch of a 2010 quarterfinal won by the Bulgarian.
The Williams sisters have combined to win nine of the past 11 Wimbledon singles titles, and while Serena has played only five matches in the past 11½ months, and Venus missed about five months with a hip injury, both are clearly capable of producing top-level tennis.
"Yeah, I'm still alive, and it feels good," said Serena Williams, who could become the first woman since Steffi Graf in 1991-93 to win Wimbledon three years in a row. "You know, I'm hoping to be around ... a lot longer."
Also in the picture are top-seeded Caroline Wozniacki, hoping for her first Grand Slam title, and 2004 Wimbledon champ Maria Sharapova.
"Well, there's no doubt you have to improve with the second week coming. I think that's always the toughest part," said Sharapova, who's won three major titles but none since 2008. "That's where you hope you raise your level."
The top four men — Nadal, No. 2 Novak Djokovic, No. 3 Federer and No. 4 Andy Murray — filled out the semifinals at the French Open, and no one would be too surprised if they did that again at Wimbledon. They lost a total of three sets during Week 1.
One thing to keep an eye on Monday: Nadal's fitness. He slipped behind the baseline a couple of times during his third-round victory over Gilles Muller, and afterward acknowledged he was bothered by a right leg muscle. But he also said he can "play with that, without problems."
Venus Williams' straight-set loss against Pironkova a year ago represented only the third time in the American's past 11 trips to Wimbledon that she didn't reach the final.
"Last year, I let a few games get away, and instead of coming back, I let it all get to me," she said. "You can't do that, especially in a Wimbledon quarterfinal. I won't let anything get to me this time."