It’s no secret Elena Rybakina has had Elise Mertens’ number for much of her WTA Tour Driven by Mercedes-Benz career. Entering Monday’s fourth-round match at the Australian Open, she had beaten the Belgian five straight times.

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Make it six. Rybakina defeated the No. 21 seed 6-1, 6-3 in 1 hour and 17 minutes to advance to the quarterfinals in Melbourne for the second time, and the first time since reaching the final in 2023.

It’s her first Grand Slam quarterfinal since making the Wimbledon semis in 2024.

“I think movement was a bit better than the previous matches. Also, the serve was working,” Rybakina said to press. “Today was hot, so the ball was flying a lot. I got some good service games.

“I think the return was also not bad. I had a lot of opportunities to step in on the second serve. That’s what I tried to do. Overall, I think the match was a good one.”

Rybakina began the day tied for sixth in aces among the women’s field in Melbourne. After hitting 10 more against Mertens, she’ll likely end it tied for second with 24. She’ll have a chance to take over the top spot in her next match, as leader Wang Xinyu (27) fell in the Round of 16 to Amanda Anisimova on Monday.

But while her serve was its usual weapon, it was her return game that carried her through, especially against Mertens’ second serve. And on a day when the Belgian landed just 47% of her first serves, that was enough to swing the match in her favor.

Rybakina saved a break point in the opening game, then watched four break chances slip away in the second game before finally converting her fifth. Fittingly, it was a crosscourt forehand winner off a second serve that set up the opportunity. In fact, each of her last three break points in the game came as a result of forehand winners.

Two games later, she broke again, this time at love. She pounced on another second serve with a backhand winner for a 4-0 lead. Mertens then held for 5-1 to get on the board, but Rybakina’s seventh ace brought up set point, leading her to claim the first set in just over half an hour.

The two traded holds through the first four games of the second set before the 30-year-old’s struggles resurfaced. Rybakina again punished a second serve with a backhand winner to reach break point, then followed with another winner off the backhand wing to break for 3-2.

After saving one match point, Mertens double-faulted to give the World No. 5 a second chance to break her way to victory, and Rybakina capitalized with her 32nd winner to move into the quarterfinals.

With the victory, she now owns more wins over Mertens (seven) than any other player on tour. She’ll face Iga Swiatek in the quarterfinals, and in 11 meetings, Swiatek leads their head-to-head 6-5.

“Yeah, we played many times. Of course, I know that I need to stay aggressive and go for my shots. When we played here, it was I think also hot, so the ball was flying.

“We will see what’s going to be the conditions, who is going to win. But definitely focus for me is my serve, stay aggressive.”

If Rybakina can even that series, she’ll reach the semis in Melbourne for the second time and move one step closer to her first Daphne Akhurst Memorial Cup.

Notable stats for Rybakina:

First-serve percentage: 65% (32/49)
First-serve points won: 72% (23/32)
Second-serve points won: 71% (12/17)
Aces: 10
Double faults: 1
Winners: 32
Unforced errors: 22
Break points won: 4/9 (44%)
Net points won: 6/11 (55%)