She stalks the baseline beneath a boiling sun, her sweat glistening. She scowls. Her lips are pursed, her fists clenched.
A moment later, Dinara Safina, ranked as the best women's tennis player in the world, is smiling, batting autographed balls into the crowd after her win Wednesday at the L.A. Women's Tennis Championships at the Home Depot Center in Carson.
Her scowl is absent, her lips and fists now relaxed.
That much is obvious.
What's hidden, though, is that she is without pain, something she played with and had to take pills for during six tournaments this year.
Didn't hear about it? She didn't make a big deal about it.
"I don't like to find excuses," she said after defeating Daniela Hantuchova, 6-2, 6-4, meaning Safina, seeded No. 1 in this 56-player draw, advances to the third round to play the eighth-seeded player, Jie Zheng.
"This is my personality," Safina said. "On the court, I will never call trainer if I have a headache. If I call for somebody, it must be really bad."
Her being pain-free should be a plus in this tournament, where she is the defending champion, especially since one of her main competitors, Maria Sharapova, won Wednesday night, 6-7 (4), 6-4, 6-2, in a wildly back-and-forth match against Victoria Azarenka.
Starting with the Porsche Tennis Grand Prix in Germany through Wimbledon, Safina said she was taking up to 100 milligrams of anti-inflammatory pills to help mask the pain of a patella inflammation in her left knee.
During that time, her serve wasn't as overpowering as it can be because she often couldn't bend that knee.
"Sometimes I would see stars every time I had to bend."
Her most recent tournament, the Banka Koper Slovenia Open in late July, was her first without taking any pills, she said. She won there too, and after it was over, she told her coach, "I can finally serve without pain.' "
Good news for her, bad for others.
"Now I can serve now for half an hour without problems," she said. "Before, it would be, 'OK, let's serve half a basket and then see.' "
That's not the only difference for the 23-year-old Russian.
Though Safina seemed crisp in her win against the No. 26-ranked Hantuchova, her serves and returns screaming off the racket with precision and maneuvering the court with ease, Safina's coach Zeljko Krajan wasn't impressed.
"It was average, but it was enough."
That's a key difference from last year, Krajan said, because at that point, "when she would play average, she would lose."
"I'm more mature," said Safina, who has been at No. 1 for 16 straight weeks. "Before, I would play average and be down on myself and I would be very negative. Now I'm trying to take everything positive."
She has won tournaments in Rome, Madrid and Slovenia, is projected to make more than $9 million in prize money this year, and after her match Wednesday she was told she was the first to qualify for the season-ending Sony Ericsson Championships, in Doha, Qatar, in late October.
"Last year I was fighting until the end just to qualify," Safina said, "so it feels good."
Just like her.