Melbourne - Music fans will soon get to hear the symphonic-like shrieking that Victoria Azarenka brings to her tennis.
The No 1-ranked player and reigning Australian Open champion is known as one of the more vocal players on the women's tour, accompanying almost every whack of the ball with a high-pitched "Ooooooouuuuuuuuuuuu."
In a silent stadium, the sound can linger in the air.
Azarenka's friend, the American rapper Redfoo, who has produced multiple hit singles, has recognised some musical potential in the shriek. He recorded it and has mixed into a new song due to be released soon, she said on Monday.
"It's my grunt. It's not my vocals," Azarenka said, clarifying that she was not recorded singing. "I don't take high-key or low-key there. It's just natural."
Center court at Melbourne Park got a 57-minute Azarenka concert on Monday as she beat Elena Vesnina 6-1, 6-1 in the fourth round and continued her confident run toward the defence of her title. Going into the quarter-finals, Azarenka has dropped only one set.
Known for his wild hair and even wilder music, Redfoo has been seen cheering from Azarenka's players' box and signing autographs during most of her matches. Azarenka was quoted as telling Australian media that Redfoo, the LMFAO frontman whose real name is Stefan Kendal Gordy (he's the son of Motown Records founder Berry Gordy), had to fly off to a gig in Malaysia but plans to come back later in the week.
As an insider to the music world, Azarenka gets to listen to tunes the public hasn't heard yet - like a remix by Redfoo's DJ friend GoonRock that she called "Sweet Baby" and says is "really good."
"Sweet Baby" was piping into Azarenka's earbuds as she walked onto centre court on Monday, as she often does soaking in some last-minute musical inspiration before turning to tennis.
"If it's bad music, it's going to be a bad match," she said. "So I really choose it very carefully."
Music is a "very important" part of her pre-match preparation, Azarenka told a post-match news conference.
It helps "focus, pump you up, get your feet a little bit moving, kind of get excited," she said. "I kind of get in the zone.
"It just makes me feel good inside. When I feel good inside, I love to go out there and do the best job as I can."
The 23-year-old Belarussian rose to the top of the rankings after winning last year's Australian Open and has stayed there for all but a few weeks ever since. She needs to defend her title to hold the top spot from No 2 Maria Sharapova or No 3 Serena Williams.
All three top-ranked women remain in contention, meaning the women's quarter-finals contains all of last year's Grand Slam winners. Sharapova won the French Open and Williams won at Wimbledon and the US Open.
Next up for Azarenka is Svetlana Kuznetsova, who entered the season's first major ranked No 75 but has won titles at the 2004 US Open and 2009 French Open.
Kuznetsova advanced after a 6-2, 2-6, 7-5 win over Caroline Wozniacki, a former No 1-player who will now slip out of the top 10.
The 27-year-old Kuznetsova said she noticed a difference in the temperament of Azarenka, who was prone in the past to hot-headed outbursts on court.
"She's changed and just become so stable," said Kuznetsova. "I think she just got calmer. She's consistent."
Going into the match feeling like the underdog gives Kuznetsova added confidence, she said.
"She's No 1. I have nothing to lose. She has all the pressure," she said. "I've got the game to give her some problems, and I will just do my best and try to enjoy it."
Azarenka smiled when told her opponent had complimented her composure.
"I'm always going to be an emotional player," she said, adding that now she's learning how to pick the right reaction for each point.
"Sometimes you need to be more aggressive ... to pump yourself up," Azarenka said. "Sometimes you just need to relax and breathe."