The Madrid Open gets underway this Thursday, as tennis’ finest challenge for one of the game’s most distinguished titles outside of the four major Grand Slams.

Held in the Spanish capital every year, the tournament is a joint men’s and women’s professional tennis event, held every year on clay in the build-up to the French Open.

It started as a men’s only competition in 2002, before a premier women’s contest was introduced in 2009.

The tournament has been notable over the years, especially for being the first event to introduce blue clay –– which has subsequently not been used since, following complaints by the likes of Rafael Nadal and Novak Djokovic.

A number of the world’s top female players are in action this week, but who has had the most success at Madrid in the past?

Maria Sharapova, Dinara Safin and Kiki Bertens are all one time winners, but here are the three women with the most singles titles to date:

Serena Williams

The 23-time Grand Slam winner has reached two finals in Madrid, winning them both in straight-sets against Victoria Azarenka and Sharapova.

The American’s first win came in 2012 –– the inaugural year of blue clay, and she defended her title a year later before winning the French Open that same season.

Williams also won the doubles title with her sister Venus in 2010, beating Gisela Dulko and Flavia Penetta 6-2 7-5.

The former world number one will be absent this year though, having recently undergone oral surgery, and is not expected to return until Rome next month.