Ashleigh Barty on Sunday, became the new world number one after winning the Nature Valley Classic in Birmingham, England.
She replaces Naomi Osaka, who has occupied the position since her 2018 US Open title.
The French Open champion triumphed over Julia Goerges 6-3 7-5 in the final.
Barty, 23, came into the tournament, knowing that winning the tournament will make her become the 27th woman to assume the WTA top spot.
The Australian didn’t drop a set on her way to the final, including in matches against Donna Vekic and Venus Williams.
She won the opening set against Georges, her doubles partner. But her opponent, who is number 19 in the world, fought back in the second to open up a 3-0 lead.
However Barty dug deep and found crucial breaks to level things at 3-3 in the second set.
She eventually found another break and served out at 6-5 to to secure the title.
Barty becomes the first female Australian world number one, since Evonne Goolagong-Cawley and fifth Australian ever. The others are John Newcombe, Pat Rafter and Lleyton Hewitt.
It is her 12th victory in a row and she is now 36-5 in 2019.
She returned in 2016 as an unranked player, and has become the best in women’s tennis in three years.
“It’s just been the most incredible journey for myself and my team” Barty said after her victory.
“And Jules, I couldn’t think of a better person to share the court with. We’ve had an incredible week on the singles and doubles courts.
“You’re one of my best friends on tour and you’ve been there for me since I was just a little tucker running around annoying everybody. She’s always allowed me to practice with her and share her experiences. She’s an incredible human being with the most amazing team and I couldn’t think of anybody better to be standing on the court with me just now.
” You always dream about it as a little kid for it to become a reality is incredible, it really is. “
“It wasn’t something that was even in my realm for this year, we were aiming for top ten and to be where we are is a testament to all the people around me.
“I have the most incredible team of people who have been with me for these last three years, we started from scratch three and a half years ago without a ranking and now to be where we are is a massive achievement for them.
“It’s been a whirlwind few weeks for me and it’s been a whirlwind year but to follow in the footsteps of Evonne, to be even mentioned in the same sentence as her is incredible and what she’s done for our sport, for Australians all around the world, she’s put us on the map and what she’s done for Indigenous Australians has just been remarkable.”