Metta World Peace -- My Daughter's a Tennis Phenom ... 'Next Big Star'

The World Peace family isn't just about basketball (even though they're really good at it) ... with Metta telling TMZ Sports his daughter is a tennis sensation ... who could be the next big superstar.

Metta took his family out to dinner at The Nice Guy in L.A. Thursday night -- when we started talking up his adorable daughter Diamond ... a 7th grader who's already got her dad thinking big things!

But could she be the next Serena? Watch the clip ...

BTW, Metta has a son who's tearing up the high school basketball world.

Talented family.