NEW YORK - Ask Rafael Nadal how his famously troublesome left knee is feeling on the eve of the US Open, and he baulks a bit while formulating a response.
"I am ..." the 12-time major champion begins.
"You know ..." he resumes, before smiling sheepishly and pausing again.
Eventually, Nadal offers something of a complicated answer, saying that he figures he needs to say he's doing well because of how well he's been playing.
He takes a 10-match winning streak into Monday against American Ryan Harrison as the year's last Grand Slam tournament begins at Flushing Meadows.
The second-seeded Nadal says it "will sound strange" if he says he still has problems with his knee. But he adds he still has "pain some days".
Meanwhile with four US Open titles already salted away, women's top seed Serena Williams could be ready to coast psychologically at this year's event.
But the world number one who was shocked last weekend with a finals loss in Cincinnati by second-ranked rival Victoria Azarenka says that while her competitive fires burn as strongly as ever, she still has the satisfaction that she has accomplished almost everything possible.
"I don't need to do anything, that's the beauty of my career," said the 16-time grand slam winner.