Former World No.1 Venus Williams notched her first Top 20 win in four years with a 6-4, 7-5 upset of No.16 seed Veronika Kudermetova in the first round of the Western & Southern Open on Monday.

Seven-time Grand Slam champion Williams, currently ranked No.533, had not beaten a Top 20 player since this very event in 2019, when she upset Kiki Bertens. Following that win, Williams had lost her next ten matches against Top 20 opposition.

However, the 43-year-old made her mark in Cincinnati once again, ousting Kudermetova in just under two hours of play, in a match which was interrupted by two rain delays.

"Definitely satisfaction from today is [from] all the work that goes into just being here at all," Williams said, after her win.

"I did my best to be here as soon as possible in the best form possible I could bring in that amount of time. So that makes it satisfying, to be able to get a win with very little time to prepare."

On Monday, Kudermetova held 4-1 leads in both the first and second sets. In fact, the World No.16 had two set points to level the match at one set apiece, one at 5-2 and another at 5-3 in the second set.

But Williams came all the way back on both occasions to polish off the win in straight sets, picking up her first victory on tour since she defeated Camila Giorgi in the Birmingham first round in June.

In their first meeting, Kudermetova had 16 winners to Williams's nine, but Kudermetova's 33 unforced errors were more than double Williams's 15. Williams converted six of her nine break points to triumph.

"I think at some point when you're down a double break, you start to think, 'Well, I at least want to just hold serve for the rest of this set,'" Williams said. "Simple thoughts like that. Then you get a little bit closer. You're like, 'Okay, maybe I just want to win another point.'

"Definitely some big holes today that I usually don't play from. ... But that's tennis. That's what's so exciting."

Another American Grand Slam champion posted a straight-sets win on Center Court on Monday to join Williams in the second round. Sloane Stephens, the 2017 US Open champion, ousted Elisabetta Cocciaretto 7-5, 6-2 earlier in the day.

Highlights: Stephens def. Cocciaretto

Stephens, currently ranked No.38, came back from 5-2 down in the first set to oust No.30 Cocciaretto of Italy and set up a second-round clash against the defending champion, No.6 seed Caroline Garcia of France. Garcia leads their head-to-head 4-2.

"Super excited," Stephens said, looking ahead to her upcoming meeting with Garcia. "Obviously I have nothing to lose and everything to gain, so I'm just going to go out and play my best and compete well and hard, and play my game."