WWE Superstar Rey Mysterio Says Son Dominik Will Be Better Wrestler

Rey Mysterio is a WWE legend ... but he won't go down as the best wrestler in the family, 'cause the Grand Slam champ tells TMZ Sports his son, Dominik Mysterio, will actually be better than him!

We talked to the 46-year-old wrestler ahead of the 30th season of Raw, premiering Monday night, and we asked about his WWE Superstar son's ascent as one of the best wrestlers in the world.

"I've told my son from the beginning, you're gonna be better than your old man and I keep saying this over and over and over to him," Rey says.

"I can't wait for the day for him to become his own man, although in a way he already is and for me it's hard as a father to kind of let him go and fly on his own, but I truly believe in my heart, and I don't just say this so he can stamp it in his head, but he's gonna be better than his old man."

That's saying A LOT ... Rey has been the World Heavyweight Champ, 3 times, Cruiserweight Champ, 3 times, Intercontinental Champ, twice ... among a bunch of other championships.

Speaking of titles, Rey and Dominik actually won the tag team title together ... a first for a father and son.

We asked Mysterio where the moment ranked in his career of awesome accomplishments ... and it was clearly an unforgettable moment.

"Top three, without a doubt!"

And, get this ... Rey says his son's success has actually motivated him to continue kicking ass in the squared circle as he ages.

"It motivates me, it inspires me to keep doing what I'm doing because I'm seeing my son kickoff!"