Rafael Nadal wears a $775,000 watch when he plays

Rafael Nadal's newest piece of equipment costs more than three-quarters of a million dollars, and yet it will probably never help him win a tennis tournament.

Nadal upgraded his on-court wristwatch to a $775,000 model made by Richard Mille for the French Open, Robert Frank of CNBC reports.

Nadal is no stranger to the world of high-end watches. In 2010 he began wearing another Richard Mille timepiece valued at $500,000. In 2013, he was wearing the predecessor to his current watch, one valued at $690,000.

Richard Mille will make only 50 of the RM27-02. It's most impressive features are its lightweight (20 grams) yet durable construction (can withstand 5,000 Gs of force).

Nadal, who's left-handed, wears it on his right wrist:

Nadal told Tom Perrotta of The Wall Street Journal that he was skeptical of wearing the watch at first.

"In the beginning there was a little bit of transition, we had to work together to adjust everything to my wrist," Nadal told WSJ. "It's like you are wearing nothing. It's part of my skin."

According to Perrotta, Nadal has lost two Richard Mille watches that were stolen (one was later recovered) and nearly lost a third when a fellow player found one in a locker room.