Ash Barty has now won eight of her last nine matches after stunning world No.9 Venus Williams to reach the third round in Cincinnati.
Australian qualifier Barty upset world No.9 Williams 6-3 2-6 6-2 on Wednesday in the second round of the key lead-up event for Flushing Meadows.
It was her first-ever win over a top-10 player.
“It feels really good. To play Venus on such a big stage is a privilege for me and to play as well as I did, I’m really excited,” Barty told the WTA website.
“She’s a genuine champion of the game and paved the way for us young players coming through.
“It’s an honour for me to … share the court with her, and happy to be moving on.”
Unfortunately, fellow Aussie Daria Gavrilova’s Cincinnati tilt is over after the 23-year-old fell in three sets to Italy’s Camila Giorgi.
Gavrilova, who upset 13th seed Kristina Mladenovic in the first round after blowing her off court in the opening set, fought back after losing a first-set tiebreaker but lost 7-6(1) 5-7 6-3.
Barty will face former world No.1 Caroline Wozniacki for a place in the quarterfinals after the sixth-seeded Dane beat Russia’s Elena Vesnina 6-2 6-4.
Ninth-seeded Williams, a finalist at the Australian Open and Wimbledon this year, fell behind 4-1 in the decisive set after dropping serve in the third and fifth games.
The 21-year-old Barty showed plenty of poise and served out the match to love to close out the contest in one hour and 50 minutes.
The world No.48 had captured the first set on her fourth set point when she drove a stinging forehand into the backhand corner that the 37-year-old Williams had no chance to reach.
Williams, in the pair’s first ever meeting, rallied in the second set as Barty’s serve fell away, but the Australian recovered to win 88 per cent points on her first serve in the decider.
Williams was full of praise for the Australian.
“She just played really well. She found openings in the court, was super consistent, and she just played really well. I just have to give her credit,” she said.