Four-time Grand Slam champion Naomi Osaka said on Wednesday she "didn't want to have regrets" after confirming that she has teamed up with Serena Williams' renowned former coach Patrick Mouratoglou.

Former world No. 1 Osaka, now ranked 73rd, defeated Lucia Bronzetti of Italy 6-3, 6-2 in the first round of the WTA 1000 China Open with Mouratoglou in her players' box.

The 26-year-old Osaka split from Belgian coach Wim Fissette this month as she attempts to return to the form that propelled her to the top of the women's game.