Currently the world's ninth-best female tennis player, Serena has dominated the sport for the past decade, winning Wimbledon four times and bringing home two Olympic gold medals. Rumor has it, she likes being a cougar within the sport too; she's allegedly currently dating 20-year-old Bulgarian tennis pro Grigor Dimitrov.
DECADE ACHIEVEMENT: Winning both Wimbledon and the U.S. Open in 2009.
83. Serena Williams