Maria Yuryevna Sharapova is a Russian professional tennis player. A United States resident since 1994, Sharapova has competed on the WTA tour since 2001. She has been ranked world No. 1 in singles by the WTA on five separate occasions, for a total of 21 weeks. She is one of ten women, and the only Russian, to hold the career Grand Slam. She is also an Olympic medalist, having won silver in women's singles at the 2012 Summer Olympics in London. Despite an injury-prone career, Sharapova has achieved a rare level of longevity in the women's game. She won at least one singles title a year from 2003 until 2015, a streak only bested by Steffi Graf, Martina Navratilova, and Chris Evert. Several tennis pundits and former players have called Sharapova one of tennis's best competitors, with John McEnroe calling her one of the best the sport has ever seen.