Paulina Gretzky -- Squeezes Out the Next Great One ... Births First Child

Paulina Gretzky and PGA fiance Dustin Johnson just produced a future all-star -- and gave Wayne Gretzky his first grandchild in the process ... TMZ Sports has learned.

Sources tell us Wayne's daughter gave birth to a boy, Monday outside of Los Angeles ... and we're told mother and child are healthy and fine.

As for the name -- all we know is it starts with a T, in keeping with a Gretzky tradition for guys. Wayne's son's are named Tristan, Trevor, and Ty.

Paulina and Dustin announced the pregnancy back in September by posting pics of her holding her belly -- but they never revealed the due date.

Let's face it ... this kid's got greatness flowing through his veins already -- so the proud parents talked to us a few months ago about baby Johnson possibly going pro someday.

Mazel!