Ashleigh Barty became only the second Australian woman to top the world rankings when she won the Birmingham WTA title on Sunday, beating Julia Gorges 6-3, 7-5.
The 23-year-old French Open champion emulates Yvonne Goolagong-Cawley, who held it for a fortnight in 1976.
Barty displaces Japan's Naomi Osaka as women's world No 1.
Even more extraordinarily, it comes less than five years since she took time out from tennis to play cricket in 2014.
"You always dream of it as a little kid, but for it to become a reality is incredible, it really is," Barty said after receiving the trophy in a tournament she had not dropped a set in. "It's not something that was really in my realm.
"We started from scratch without a ranking and now to be where we are, not only for me, is a massive, massive achievement for them."
Barty showed little sign of the arm injury - the same one she had going into the French Open - which saw her pull out of the doubles on Saturday where coincidentally she was partnering Gorges.
Barty saved two break points early in the first set but she made no mistake when she was offered the opportunity - Gorges putting a backhand wide to give the Australian a 4-2 lead.
Here's a message for you from the new WTA World No.1, @ashbar96! 🏆#NatureValleyClassic#ItTakesWTA pic.twitter.com/WoMKPRboWg
— wta (@WTA) June 23, 2019
Barty closed out the set without further ado - the pick of her shots a delightful lob into the far corner which Gorges tried valiantly to get back but it dropped short of the net to give her a 5-2 lead.
Gorges, though, struck back in the second set, breaking Barty in her first service game and the German held her own to move into a 3-0 lead.
Barty broke back, however, when Gorges sent a forehand out to get back to 3-2.
Gorges, leading 4-3, took Barty's next service game to deuce with a superb volley, but the Australian extricated herself from trouble and levelled at 4-4.
Barty had a break point in the next game but Gorges found the wherewithal to fight back and win the game to go 5-4 up.
Gorges had a set point in the next game but Barty, showing her championship winning mentality, saved it with an ace and then held serve to make it 5-5.
Barty by contrast did take her chance when it came in the following game breaking Gorges and then wrapped up the title and the top spot with her service game.
Barty said it was an honour to follow in Goolagong-Cawley's footsteps.
"To be able to follow in the footsteps of Yvonne, even to be mentioned in the same sentence as her, is incredible," Barty said. "What she's done for our sport, for Australians all around the world, not [those] just based in Australia, she's put us on the map.
"And what she's done for indigenous Australians is just remarkable."
Federer continues to win titles
Meanwhile, Roger Federer will head to Wimbledon in high spirits after waltzing past Belgium's David Goffin in straight sets to win a record-extending 10th title at the ATP event in Halle on Sunday.
Federer, 37, beat Goffin 7-6, 6-1 to secure his 102nd career singles title and remain unbeaten on grass so far this season.
"It's unbelievable. I never thought when I first played here that I would win 10 titles," Federer said. "I've never won a tournament 10 times before, so I will remember forever that I did so here in Halle."
The Swiss star is chasing a ninth Wimbledon crown in London next month as he looks to extend and defend his record of 20 career majors. Long-term rival Rafael Nadal moved to within just two titles of Federer's record with his 12th French Open triumph earlier this month, while world No 1 Novak Djokovic is just five short with 15 career majors.
Federer endured a rough ride in the early rounds in Halle, battling to hard-fought, three-set victories over Jo-Wilfried Tsonga and Roberto Bautista Agut. Things got easier in the latter stages as he thrashed Andy Murray's new doubles partner Pierre-Hugues Herbert in the semi-finals before dispatching Goffin on Sunday.
Federer held off three break points early in the first set before prevailing in the tiebreaker.
An unsettled looking Goffin then gifted Federer the opening game of the second set with a double fault on break point.
From there, the Swiss never looked back, breaking Goffin twice more on his way to a 10th Halle title.
"I thought David was actually better than me in the first 10 games," Federer said.
Goffin added: "I thought I started really well, there was great intensity in the first set. I had opportunities, but you have to take them against Roger. This guy is pretty good."
It is the first time Federer has reached double figures at any individual tournament. He has triumphed eight times at both Wimbledon and the Dubai Open, and has won his home tournament in Basel on nine occasions.
