The Williams sisters through the years

Jennifer Capriati (centre) stands with Venus Williams and her sister Serena Williams.

1992: Serena Williams and her sister Venus Williams ride with their father Richard Williams at a tennis camp in Florida. Mandatory Credit: Ken Levine /Allsport

Venus Williams (left) stands with her sister and fellow tennis player Serena Williams.

Teenage tennis sisters from America, Venus and Serena Williams pose together during the Adidas International event in Sydney, Australia. Credit: Clive Brunskill/Allsport

Serena and Venus Williams in the doubles final of the US Open in Flushing Meadows, New York.

Serena, mother Oracene and Venus Williams of the USA pose for the media during the Lipton Championships on March 20, 1999. (Photo by Al Bello/Getty Images)

Venus and Serena Williams of the USA celebrate after winning the Gold Medal in the Women's Double Match against Kristie Boogert and Miriam Oremans at the 2000 Sydney Olympic Games. Credit: Clive Brunskill /Allsport

The Williams sisters walk out on centre court for the semi-final match of the women's singles at Wimbledon. Mandatory Credit: Clive Brunskill/ALLSPORT

Venus and Serena Williams of the USA celebrate gold after winning the Women's Doubles Tennis Final at the Sydney 2000 Olympic Games. Credit: Gary M Prior/Allsport

Venus and Serena Williams in action in the women's doubles at Wimbledon in 2002. (Photo by Phil Cole/Getty Images)

Serena Williams of the USA celebrates victory against Venus Williams in the Women's Singles Final at Wimbledon in 2003 . (Photo by Alex Livesey/Getty Images)

Serena Williams and Venus Williams in the Women's Doubles gold medal match at Beijing 2008. (Photo by Clive Rose/Getty Images)

Venus Williams (L) and Serena Williams celebrate winning the Women's Doubles gold medal match at Beijing 2008. (Photo by Clive Brunskill/Getty Images)

Serena Williams and Venus Williams in action at Wimbledon 2010. (Photo by Hamish Blair/Getty Images)

Serena Williams of the United States receives treatment at Wimbledon in 2014. (Photo by Jan Kruger/Getty Images)

Serena Williams of The United States is congratulated by Venus Williams after their ladies singles match at the 2018 US Open. (Photo by Julian Finney/Getty Images)