Dominika Cibulková

Serena of the U.S. celebrates defeating Cibulkova of Slovakia to win their women's singles quarter-final match at the Australian Open 2015 tennis tournament in Melbourne...Serena Williams of the U.S. celebrates defeating Dominika Cibulkova of Slovakia to win their women's singles quarter-final match at the Australian Open 2015 tennis tournament in Melbourne January 28, 2015.     REUTERS/Carlos Barria (AUSTRALIA  - Tags: SPORT TENNIS)

Carlos Barria/Reuters

Serena Williams of the U.S. celebrates defeating Dominika Cibulkova of Slovakia to win their women’s singles quarter-final match at the Australian Open 2015 tennis tournament in Melbourne, Australia

Williams of the U.S. serves to Cibulkova of Slovakia during their women's singles match at the Brisbane International tennis tournament in Brisbane...Serena Williams of the U.S. serves to Dominika Cibulkova of Slovakia during their women's singles match at the Brisbane International tennis tournament in Brisbane, January 2, 2014. REUTERS/Jason Reed

Jason Reed/Reuters

Serena Williams of the US serves to Dominika Cibulková of Slovakia during their women’s singles match at the Brisbane International tennis tournament.