Naomi Osaka Grabs Dinner With Mom After Pregnancy Announcement

Tennis superstar Naomi Osaka had a night out with her mom in the Big Apple on Monday ... hitting up a Japanese restaurant three weeks after announcing she's preggo with her first child.

The 25-year-old and Tamaki Osaka arrived at Nippon in Midtown for dinner ... one of the few times the mother-to-be has been spotted out in public since her big reveal.

No baby bump in sight, though -- Osaka rocked a baggy brown and green outfit for the occasion.

As we previously reported, Osaka told her fans about the major life update on Jan. 11 ... and TMZ Sports confirmed rapper Cordae is the father.

"I realize that life is so short and I don't take any moments for granted, everyday is a new blessing and adventure," Osaka said in her announcement. "I know that I have so much to look forward to in the future, one thing I'm looking forward to is for my kid to watch one of my matches and tell someone, 'that's my mom,' haha."