Two-time US Open champion Naomi Osaka survived another erratic outing, beating Belgian Elise Mertens 6-3, 3-6, 7-5 on Saturday to reach the US Open fourth round.
Osaka had 41 unforced errors, her backhand in particular letting her down as she was unable to build on a comfortable first set for the second straight match.
"I'm literally shocked that I won this match," Osaka, seeded 13th, told an adoring crowd in Louis Armstrong Stadium.
Win secured. Focus unchanged 🔒 pic.twitter.com/IV9kT6BXMU
— US Open Tennis (@usopen) September 6, 2026
"There was a certain point where I felt like I put my entire heart on the court. I just kept trying every point."
After an early exchange of breaks in the second set, Osaka failed to convert a pair of chances and Mertens broke again for a 5-3 lead.
Osaka gifted the Belgian two break points with a double fault, saving one with a forehand winner before sailing a backhand wide.
Mertens finally took the set when Osaka dumped a backhand into the net.
Mertens kept the pressure on in the third and was rewarded with a break for a 3-2 lead, aided by a string of backhand errors from Osaka.
Nerves? What nerves? 🥶
— US Open Tennis (@usopen) September 6, 2026
Mertens saves match point to level the decider at 5-5. pic.twitter.com/NjQWpnsNlm
Osaka was clearly frustrated, berating herself and exchanging some testy words with her team.
"I didn't feel like I played amazing, it was really getting me down," she told the crowd, offering an apology for her behavior.
She was down a break trailing 4-3 when she took a medical timeout for treatment on her left calf and ankle.
Osaka returned with renewed vigor, breaking Mertens at love for 4-4 and saving a break point in the next game for a 5-4 lead.
Naomi survives the storm 🌪️
— US Open Tennis (@usopen) September 6, 2026
Osaka battles past Mertens 6-3, 3-6, 7-5 after a dramatic deciding set. pic.twitter.com/1F4m2VyE4R
Mertens didn't go quietly, saving a match point on the way to 5-5 and saving two more in the final game before Osaka secured the win.