Tennis has been transformed over the last five decades by TV, money, technology, equipment, fashion and politics. But through all of that, the players have remained at the heart of the game. As part of our golden anniversary celebration of the Open era, Tennis.com presents its list of 50 best players—the Top 25 men and the Top 25 women—of the last 50 years. You'll be able to view the entire list in the March/April issue of TENNIS Magazine.

(Note: Only singles results were considered; any player who won a major title during the Open era had his or her entire career evaluated; all statistics are through the 2018 Australian Open.)

Years played: 2001—

Titles: 36

Major titles: 5

“I just remember being on the ground,” Maria Sharapova told the Daily Telegraph on the 10th anniversary of her 2004 Wimbledon title, “and looking up at the [player] box and shaking my head and saying, ‘Did this really happen?’”

“It was so inspiring and so unexpected.”

Sharapova wasn’t kidding. In 2004, the idea that a slender 17-year-old who had played Wimbledon just once could go toe-to-toe with Serena Williams on Centre Court and come out a straight-set winner was earth-shaking. So much so that Sports Illustrated granted tennis a rare cover, with Sharapova posed under the same words they had used to describe a young Tracy Austin 30 years earlier: “A Star is Born.”

Sharapova lived up to the billing, on and off the court. This Russian-born, American-bred young woman would become one of the game’s most bankable players and, more importantly, one of its best and most committed competitors. Over the next decade, the sport’s milestones fell to her one by one. In 2005, she ascended to No. 1; in 2006, she won the US Open; in 2008, she won the Australian Open and helped Russia to the Fed Cup title; in 2012, after recovering from a career-threatening shoulder injury, she became the second woman in this century, after Williams, to complete a career Grand Slam when she won the first of her two French Opens. With her high-decibel grunts and high-profile endorsements, Sharapova was the most visible and audible member of a Russian wave that washed over the game at the start of the century.

Tennis Channel presents: Unstrung, Maria Sharapova

Yet Sharapova is associated less with her accomplishments than she is with how she accomplished them. Experts and pundits from John McEnroe on down have called her one of the fiercest fighters the sport has seen. When she was six, she was singled out by Martina Navratilova at a clinic in Moscow. “I liked the way she walked,” Navratilova said. From the start, the Sharapova strut and grunt signaled an ambition that few players had rarely made so overt—or so loud.

At 6’2”, she was blessed with height and power, but according to one of her early coaches, Robert Lansdorp, what she was really blessed with was determination. Through countless hours of target practice, they honed her laser ground strokes. That same determination transformed her from a self-described “cow on ice” on clay, in her early years, into a two-time champion at Roland Garros.

Still, no amount of ambition and determination has been enough to get Sharapova back to where she started in 2004: celebrating a victory over Serena. From 2005 to 2016, she lost 18 straight times to the American. Worse, in 2016 Sharapova was suspended for 15 months after testing positive for a banned substance.

Does Sharapova, now 30, have the determination to rise to the top of the game again? Everything about her career says yes.

Defining Moment: Sharapova will always be remembered for her breakthrough win over Serena at Wimbledon in 2004, but just as impressive and surprising—and even more characteristic—was her 2012 French Open title. Clueless on clay in her early years, Sharapova willed herself to become one of the best dirt-ballers of her era.

Watch: Maria Sharapova beats Serena Williams to win 2004 Wimbledon title

This Week on Tennis Channel Plus 2/12

ATP Buenos Aires (Feb. 14-18)

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ATP Rotterdam (Feb. 13-14)

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