Osaka reaches her biggest grass quarterfinal ever with a commanding win over Elise Mertens.
Naomi Osaka delivered one of the most assured performances of her grass-court career today, dismantling world No. 26 Elise Mertens 6-3, 6-3 in the second round of the Bad Homburg Open to reach her first quarterfinal at a WTA 500 grass-court event. The four-time Grand Slam champion progressed without dropping a set, making this the highest-level grass quarterfinal of her career.
Osaka in control from the first game
The sixth-seeded Japanese player came out firing from the opening point, building a 5-0 lead before Mertens briefly steadied herself and won three consecutive games. The response was short-lived. Osaka regrouped immediately, took four of the next five games to close out the first set 6-3, then secured her fourth break of the match in the ninth game of the second set to wrap up victory.
The numbers made for impressive reading. Osaka fired seven aces, won 86% of her first-serve points and finished with 22 winners against just eight unforced errors. Mertens managed 12 winners but gave away 16 unforced errors and won fewer than 40 total points across the match.
Fast work from Naomi #Osaka — into the quarterfinals in just 67 minutes! 🎾#BHO26 pic.twitter.com/sVvMtzsmuN
— Bad Homburg Open powered by Solarwatt (@badhomburgopen) June 23, 2026
Attitude, and a call home
After the match, Osaka was asked which part of her performance pleased her most. She pointed to her mental stability rather than her shot-making. In her opening-round win over Magdalena Frech, she had experienced a noticeable drop in level during the first set. Today she made a deliberate effort to stay more consistent throughout and came away feeling she had achieved it. She also described how she plans to spend her evening between matches: calling her daughter, reading books and playing games before the night slips away.
A grass-court record quietly rewritten
Osaka’s quarterfinal run at Bad Homburg builds on a grass-court history that had previously offered only modest milestones. She played her first grass quarterfinal over a decade ago in Kurume, Japan, losing to compatriot Nao Hibino. A year later she won one for the first time in Surbiton, England, reaching the final of that event. Her first tour-level grass quarterfinal came in Nottingham in 2018, where she beat Mihaela Buzarnescu before falling to Ashleigh Barty in the semifinals. Most recently, she appeared in the last eight at ‘s-Hertogenbosch in 2024 but lost to Canada’s Bianca Andreescu. Bad Homburg is a level above each of those.
Osaka had been set to open her grass season in Berlin the previous week but withdrew, opting for additional preparation time. Two straight-set wins at Bad Homburg suggest that time was well spent.
Osaka’s path through Bad Homburg
Her quarterfinal opponent will be determined Wednesday, when reigning French Open champion Mirra Andreeva takes on Ekaterina Alexandrova in their opening match. Andreeva, the tournament’s second seed, has not played since winning Roland Garros three weeks ago. A meeting between Osaka and Andreeva would be their first career encounter.
Should Osaka advance, potential semifinal opponents include Elina Svitolina and Wang Xinyu. The draw from there could feature Iga Swiatek, Qinwen Zheng and Karolina Muchova. Swiatek lost the Bad Homburg final a year ago and went on to win Wimbledon the following week. For Osaka, who has never passed the third round at the All England Club, a deep run this week would be the strongest grass-court statement of her career.