Tennis legend Billie Jean King presents Serena Williams of the U.S. with the trophy after the women's singles final tennis match of the WTA Finals at the Singapore Indoor Stadium

Billie Jean King is a legend and considered one of the greatest in her own right so her opinion on who’s the best tennis player is major.  She had no hesitation when asked.

It ain’t Martina. It’s not Steffi … Andre, Pete or McEnroe — the greatest player to ever step on the tennis court is SERENA WILLIAMS so says Billie Jean King.

In the past, Billie has raved about Serena’s potential, saying she has what it takes to be #1.

Fast forward to Wednesday and BJK tells TMZ Sports she’s convinced, Serena’s the best to ever do it.

Shay Marie: Twitter || Instagram