Halep on top of the world - but who else has been No.1 in 2017?
Finally, Simona Halep will be crowned number one in the world.
With a straight-sets victory over Jelena Ostapenko in the semi-finals of the China Open, Halep made sure she will be at the summit when the new WTA rankings are released on Monday.
The Romanian, who had narrowly fallen short of securing top spot on three previous occasions in 2017, will become the 25th woman to achieve the feat since the computer rankings were introduced in 1975.
She will also be the fifth different player to be at number one in 2017. Here we look at the previous occupants during a see-saw year on the WTA Tour.
By winning the US Open last year, Kerber followed in the footsteps of fellow German Steffi Graf in occupying top spot. At 28, she became the oldest player to debut in the position.
Kerber also won the Australian Open in a hugely successful 2016, but has struggled to hit the same heights this year. Blighted by a shoulder injury, her only final appearance resulted in a defeat to Anastasia Pavlyuchenkova in Monterrey.
Difficult roads often lead to beautiful destinations! pic.twitter.com/R1nEaBw3Vc-- Angelique Kerber (@AngeliqueKerber) June 2, 2017
Williams has enjoyed two spells at number one this year. She was on top of the world after her victory at the Australian Open in January, then - despite not playing since the major in Melbourne - briefly reclaimed the honour in April.
The American - a 23-time grand slam winner - was out of action at the time of her second promotion, having announced she was pregnant with her first child. On September 1, Williams gave birth to Alexis Olympia Ohanian Jr.
It's very weird for me to believe I have a child... a KID. I'm a mom. A real MOM-- Serena Williams (@serenawilliams) September 18, 2017
Pliskova made history with her rise in the rankings. Following her victory in the final of the Eastbourne International, the 25-year-old became the first female representing the Czech Republic to achieve the honour of holding the No.1 position.
Her success on grass made it three WTA Tour titles for the year, following on from previous triumphs in Brisbane and Doha. Pliskova has yet to win a slam, though, losing the 2016 US Open final to Kerber.
Born in Venezuela but raised in Spain, Muguruza became the second Spaniard to reach the summit (Arantxa Sanchez-Vicario was the other) in September. In reaching the second week of the US Open, the 23-year-old usurped Pliskova in the rankings.
The elevation was just reward for the consistent Muguruza, who was crowned Wimbledon champion in July. She also won in Cincinnati the following month, beating new number one Halep in the final.