Rafael Nadal doesn't want to acknowledge the injury everyone is talking about, but it won't be far from the front of his mind over the next 48 hours.
Nadal suffered an abdominal injury in his third-round victory over Nicolas Almagro on Sunday. Whether it's a mere twinge or something more serious could have a seismic impact on this U.S. Open.
The world's third-ranked player wouldn't pander to questions about the ailment, which required a few minutes of treatment during the match at Arthur Ashe Stadium – and a few hours of it following his straight sets win.
It was already going to be hard enough for the Spaniard to prevail at Flushing Meadows for the first time. He'd just returned to the tour following treatment for tendinitis in his right knee.
This will make it even tougher, but underestimating Nadal is dangerous business.
The 23-year-old has made a career out of confounding critics, and there is evidence that his uncompromising and bloody-minded mentality is starting to crank into top gear.
"I don't want to talk about injuries," he said. "I am tired of talking about injuries. I am normally happy but I came here and everybody just wants to talk about injuries. I really don't want to talk about that."
Next up for Nadal is Gael Monfils, a tricky opponent who has beaten him before. But, realistically, Nadal's toughest foe before the semifinals will be his own physical condition.
Injuries struck again Sunday, with two men's singles matches shortened by physical problems. Gilles Simon, the No. 9 seed, withdrew against Juan Carlos Ferrero with a knee injury. Jose Acasuso quit while two sets down to Monfils.
Once again, it was all too easy for Serena Williams as she took another step toward what looks like an inevitable 12th Slam triumph.
Williams destroyed Daniela Hantuchova while losing only two games. She looks absolutely unstoppable heading into the second week.
For a potential shock Monday, look no further than John Isner, the man who dumped Andy Roddick in Saturday night's epic match. Isner takes on 10th-seeded Fernando Verdasco. He has a tremendous chance to win if he serves like he did against Roddick.
Isner could be helped if the match runs late – his booming serve is even harder to handle under the lights.
Match of the day
A peculiar contest on Arthur Ashe court provided the day's most gripping drama. Kim Clijsters swept through the first set against Venus Williams 6-0, lost the second by the same score then won the clincher 6-4 to reach the quarterfinals.