Victoria Azarenka knows that her notorious grunting makes Monica Seles sound tame — and she remains unapologetic about it. The 21-year-old Belarusian says the shrieking helps her accelerate and deliver more power to the ball — skills that have taken her to the quarterfinals at four Grand Slams and helped her climb to No. 4 in the world rankings in 2011. Azarenka, a fierce baseliner, moved to Scottsdale, Ariz., when she was 15 thanks to generous support from hockey star Nikolai Khabibulin and his wife, a friend of her mother’s. She attributes the rise of tennis stars from the former Soviet Union to the economic turmoil that followed its collapse. As she says, “a lot of the players come from families who don’t have money, so they have that extra hunger to try and become somebody.”