Novak Djokovic (Serbian: Новак Ђоковић or Novak Đoković; pronounced [nɔ̂ʋaːk dʑɔ̂ːkɔʋitɕ] ( listen); born 22 May 1987) is a Serbian professional tennis player who has been ranked World No. 1 by the Association of Tennis Professionals (ATP) since 4 July 2011. He has won five Grand Slam singles titles: the 2008, 2011 and 2012 Australian Open, the 2011 Wimbledon Championships, and the 2011 US Open. By winning three Majors in 2011, Djokovic became the sixth male player in the open era to win three Majors in a calendar year.

He is the first male player representing Serbia to win a Major singles title and the youngest player in the open era to have reached the semifinals of all four Grand Slam events, separately and consecutively. Amongst other titles, he won the Tennis Masters Cup in 2008 and was on the team which won the 2010 Davis Cup. He also won the bronze medal in singles at the Beijing Olympics in 2008. He has won 11 Masters 1000 series titles placing him joint fourth on the all time list. Djokovic has quickly moved up in the rankings of history. Tennis Channel ranked him number 40 , and former player Pat Cash said he is one of the greatest ever.

Serena Jameka Williams (born September 26, 1981) is an American professional tennis player and a former world no. 1. The Women's Tennis Association has ranked her world no. 1 in singles on five separate occasions. She became the world no. 1 for the first time on July 8, 2002 and regained this ranking for the fifth time on November 2, 2009. She is the only female player to have won over $35 million in prize money.

Her 27 Grand Slam titles places her ninth on the all-time list: 13 in singles, 12 in women's doubles, and 2 in mixed doubles. She is the most recent player, male or female, to have held all four Grand Slam singles titles simultaneously and only the fifth woman in history to do so. She was also the first woman, along with sister Venus Williams, to hold all four Grand Slam doubles titles simultaneously since Martina Hingis did so in 1998. Her 13 Grand Slam singles titles is sixth on the all-time list. Williams ranks fourth in Grand Slam women's singles titles won during the open era, behind Steffi Graf (22 titles) and Chris Evert and Martina Navratilova (18 titles each). She has won more Major titles in singles, doubles, and mixed doubles than any other active player, male or female.