PALM BEACH GARDENS, FL, USA – She clinched it during the US Open, but this week it’s official – Serena Williams has the WTA Year-End World No.1 Singles Ranking presented by Dubai Duty Free.

It was another phenomenal year for Williams, of course highlighted by winning her 19th, 20th and 21st Grand Slam titles at the Australian Open, French Open and Wimbledon, putting her even closer to Steffi Graf’s Open Era record of 22 Grand Slam titles and Margaret Court’s all-time record of 24.

But there was so much more, including a 53-3 win-loss record, the only losses coming to Petra Kvitova (Madrid semifinals), Belinda Bencic (Toronto semifinals) and Roberta Vinci (US Open semifinals). She now has the two best season winning percentages on the tour since 1990 (.951 in 2013, .946 in 2015).

Williams also achieved a whole new level of dominance on the WTA Rankings in the summer – for six weeks the World No.1 actually had more than twice as many ranking points as the World No.2, which had never happened before in WTA Rankings history. Maria Sharapova was No.2 for three of those weeks (July 13 to August 2) and Simona Halep the other three weeks (August 24 to September 13).

But back to the present day, and it’s all about year-end No.1 – and this is the fifth time Williams has achieved that honor, making her just the fourth player in WTA history to do it five or more times.

Here’s the full list of players to have held year-end No.1 and the years they did it:
8 – Steffi Graf (1987, 1988, 1989, 1990, 1993, 1994, 1995, 1996)
7 – Martina Navratilova (1978, 1979, 1982, 1983, 1984, 1985, 1986)
5 – Chris Evert (1975, 1976, 1977, 1980, 1981)
5 – Serena Williams (2002, 2009, 2013, 2014, 2015)
4 – Lindsay Davenport (1998, 2001, 2004, 2005)
3 – Justine Henin (2003, 2006, 2007)
3 – Martina Hingis (1997, 1999, 2000)
2 – Monica Seles (1991, 1992)
2 – Caroline Wozniacki (2010, 2011)
1 – Victoria Azarenka (2012)
1 – Jelena Jankovic (2008)

This article used insights from WTA partner SAP, a worldwide leader in enterprise software.