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.

Casey Dellacqua (born 11 February 1985) is an Australian professional tennis player who currently resides in Perth, Western Australia. She was previously coached by former Australian player Nicole Pratt, before the two decided to part ways prior to the 2009 Australian Open. She won her first Grand Slam title in the 2011 French Open – Mixed Doubles, partnering with American Scott Lipsky.

She is of Italian descent through her father and Irish through her mother.

Dellacqua attended Woodvale Primary School from kindergarten to year 7, and then attended Woodvale Senior High School before moving to Canberra to train with the Australian Institute of Sport at the age of sixteen. Throughout her early life Dellacqua was an active member of local tennis clubs and teams.

In 2007, she won singles tournaments in 2007 Melbourne, Perth, Kalgoorlie, and The Bronx, in New York.

Dellacqua began the year by reaching the fourth round of the Australian Open and upset 15th-seeded Patty Schnyder and former champion and World No. 1 Amélie Mauresmo but eventually lost to third seed Jelena Janković. The performance meant she surpassed Alicia Molik to become the highest ranked Australian female tennis player.