WASHINGTON -- Naomi Osaka and coach Patrick Mouratoglou are done working together after less than a year, the four-time Grand Slam champion announced Sunday on social media.

Emma Raducanu picked up her best win by ranking since May, ousting No. 7 seed Marta Kostyuk in the opening round of the Mubadala Citi DC Open on Tuesday. She will face former World No. 1 Naomi Osaka in the second round.

Maria Sakkari is applauding Naomi Osaka's decision to play a WTA 125 (Challenger) tournament and reveals she privately approached the four-time Grand Slam champion to tell her how much she respected her move.

Emma Raducanu dominated her first career matchup against Naomi Osaka, winning the showdown at the D.C. Open on Thursday between past U.S. Open champions 6-4, 6-2. Raducanu, the only qualifier to claim a Grand Slam title when she did that in New York in 2021,