PALM BEACH GARDENS, FL, USA – On Monday, though she’d already clinched it at the US Open, Serena Williams officially got her hands on the WTA Year-End World No.1 Singles Ranking presented by Dubai Duty Free. It was her third year-end No.1 finish in a row, and the fifth in her illustrious career.

But by achieving that feat, she’s unlocked another feat that hasn’t been done in 25 years.

Serena is the first player since 1990 to hold No.1 from start to finish two years in a row.

That means two years in a row, start to finish, not letting any other player get to No.1 for even a single week. She’s one of only three players in the history of the WTA Rankings to achieve the feat:

Martina Navratilova
– held No.1 start to finish two straight years (1983, 1984)
– overall streak at No.1: 156 weeks (June 14, 1982 to June 9, 1985)

Steffi Graf
– held No.1 start to finish three straight years (1988, 1989, 1990)
– overall streak at No.1: 186 weeks (August 17, 1987 to March 10, 1991)

Serena Williams
– has held No.1 start to finish two straight years (2014, 2015)
– overall streak at No.1: 143 weeks (February 18, 2013 to present)

Williams will add seven more weeks to that total during the off-season – her 150th straight week at No.1 will be the last week of the off-season, the week running December 28, 2015 to January 3, 2016.

All of this doesn’t just mean fighting off other players who have absolutely nothing to lose against her match after match and tournament after tournament, but putting in the hard work away from that match court to be ready for all of those challengers. And she seems to have that art down to a science.

“I compete a lot against my own standards, probably even more – I have such high standards for myself and expect the best from myself, and nothing less,” she explained earlier this year in Cincinnati.

“My main goal is to stay healthy, but I have other goals, usually around doing well in tournaments. I like being ranked No.1, too, so I try and do well enough so I can stay on top. That motivates me well.”

Stay tuned to wtatennis.com to see if the World No.1 can make it three years in a row in 2016!

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