Rafael Nadal took a well-deserved break after winning his 14th French Open ... hitting the Spanish seas with his pregnant wife and friends on an insane mega-yacht!
The No. 4 ranked tennis star was spotted on the 78-foot, multimillion-dollar catamaran yacht named "Great White" just days after beating Norwegian Casper Ruud in the major tourney -- setting a new record with 14 French Open title wins.
And, the champ was celebrating like someone who just made history ... diving into the water, and hanging out on the deck with his buddies.