And it has left the Australian hot favourite for the women’s title at Wimbledon next month.
Barty pulled off a 12th successive WTA win on Sunday to add the Nature Valley Classic to her French Open triumph.
Barty, 23, beat German Julia Goerges 6-3 7-5 in 88 minutes at the Edgbaston Priory Club in Birmingham.
She now replaces Naomi Osaka at the top of the rankings after climbing from second spot.
Barty, the first Australian in 43 years to climb to the top, reflected: “It’s an amazing place to be.
“Particularly at the French, it felt like a whirlwind.
“This week felt more like a regular week if there’s such a thing just to try and go about things the right way.
“It’s hard to put into words what we have been able to achieve over the last few years and to be where we are is just incredible.
“But certainly nothing changes now.”
Barty did not drop a set all week and took the first set comfortably to pave the way for a sixth WTA title.
But she had to show steel to recover from 3-0 down in the second and saved a set point with an ace in the 10th game before breaking Goerges in the next and serving out to love.
Barty is just the second Australian woman to become world No.1 after Evonne Goolagong Cawley in 1976.
Barty, after a standing ovation and a warm hug from her doubles partner Goerges, added: “You always dream about being No.1 as a little kid but for it to become a reality it’s incredible and not something that was even in my realm as we were aiming for top 10 this year.”
Barty headed straight off from Brum to Eastbourne for her next grass-court tournament ahead of going to the All England Club.
But her route to the top has been unconventional.
The former junior Wimbledon champion took an indefinite break from tennis at the end of 2014, recently citing mental health issues as the reason, and played Big Bash cricket for Brisbane Heat before returning to the sport in 2016.
Since then the Queenslander’s rise has been remarkable.
This month she became the first Australian woman to win the French Open for 46 years.
She added: “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 me and my team.”
Goerges, ranked world No.19, said: “She served an ace when I had set point so I think that says it all.
“It was a high-quality match and she deserved to win.
“I did everything I could but she was better.”