Focus on Federer, Nadal, 2 sisters at Wimbledon

Switzerland's Roger Federer returns a shot to Argentina's David Nalbandian... Serena Williams of the US celebrates her win over Russia's Maria Kirilenko... Serena Williams of the US serves a ball to Russia's Maria Kirilenko during... WIMBLEDON, England (AP) - Roger Federer insists he hasn't been fretting about when or—perhaps more to the point—whether he will win a 17th Grand Slam championship. "I don't go through days thinking, like, 'My God, I haven't won a Grand Slam in so long,'" Federer said. "It hasn't been that long, to be honest." Well, only by his remarkably high standards: His record-extending 16th major trophy came at the Australian Open in January 2010. That nearly...