WIMBLEDON — Aryna Sabalenka won her first Grand Slam title nearly six years ago at the US Open. She had a partner in crime, Elise Mertens, and they would repeat that doubles triumph two years later at the Australian Open.

This was before Sabalenka became an irresistible force in singles, a three-time major champion and found herself closing in on a one-year reign as No. 1 in the PIF WTA Rankings.

It’s probably not a coincidence that Sabalenka has now beaten Mertens in 11 of their 13 singles meetings, most recently on Sunday, 6-4, 7-6 (4), in the fourth round at the All England Club. For in those years of their partnership, Sabalenka came to know the intricacies of Mertens’ game, her strengths and, more importantly, her weaknesses.

Sabalenka, who has more wins against the No. 24-seeded Mertens than any other player on the Hologic WTA Tour, advances to Tuesday’s quarterfinals. She’ll face 37-year-old Laura Siegemund, who ended the unlikely run of lucky loser Solana Sierra with a 6-3, 6-2 victory.

Sabalenka finished with six aces and won 32 of 38 first-serve points. And while both players had 18 unforced errors, Sabalenka had 36 winners, nine more than Mertens. 

Sabalenka is:

• The first woman to reach the quarterfinals in all of their first three Grand Slam appearances as World No. 1 since Lindsay Davenport (Australian Open 1999 and 2005, and Roland Garros 2005).
• Improved her tiebreak record to 16-1 (including 14 straight) this season. 
• The first woman to reach the quarterfinals at all three Grand Slam played in 2025 — Iga Swiatek can equal this record on Monday.
• The fourth woman in the last 30 years to reach the quarterfinals at each of the first three Majors of the season without dropping a set in the first four Rounds after Venus Williams (1998), Kim Clijsters (2006) and Justine Henin (2006).

Sabalenka, sporting fingernails painted a becoming shade of Wimbledon green, is on a terrific tear at the Grand Slams. She’s reached the quarterfinals (at least) in the past 10 majors in which she’s appeared. Her 16 Grand Slam match-wins are more than any other woman this year, as are her 46 overall wins. 

Mertens, currently ranked No. 19, remains a formidable player at the age of 29. The Belgian won the title at the Libema Open last month and came into this match with a career record of 15-7 at Wimbledon. She’s got some pop in her shots, anticipates well and is quite handy at net. This was her third appearance in the fourth round.

The players traded breaks in the opening set — Sabalenka scored in the fourth game and Mertens countered in the seventh. But with Mertens serving at 4-5, Sabalenka cranked up the decibels and the pace. A terrific return forced a Mertens netter forehand for set point. Sabalenka followed up by blasting a backhand winner — and a scream that matched it in intensity.

Mertens, however, was undeterred. She broke Sabalenka in the third game of the second set. But serving at 3-2, Sabalenka broke back. 

This is the essence of the three-time Grand Slam champion’s game: At deuce, Sabalenka took a second serve and smoked a cross-court backhand that hit the line, sending up a small cloud of chalk. Then raised her level on the next point and Merten couldn’t land her forehand.

The decisive blow in the second-set tiebreak was a backhand laser return from Sabalenka with Mertens serving a 3-all. She closed it out with a wonderful forehand volley that Mertens could barely get a frame on.

Mertens is now 0-6 against No. 1 players for her career, half of those losses coming to Sabalenka.