1) Show up to a massive European soccer awards ceremony to watch his Paris Saint-Germain teammate, Kylian Mbappe, be honored for being a STUD this season

Or, 2) ... BLOW IT ALL OFF AND HANG WITH RIHANNA!!!

Obviously, you saw what Neymar chose.

The 27-year-old had been expected to attend the prestigious Union Nationale des Footballeurs Professionnels (UNFP) Football Awards Ceremony in Paris ... but RiRi called, so he was out!

Instead, Neymar turned up to the Boum Boum nightclub in Paris to help Rihanna celebrate the launch of her new luxury fashion brand.

Neymar posted a pic of the two hanging out with the caption ... "Queen and powerful woman 👑🤫 @badgalriri."

As for Mbappe ... he did okay (even without Neymar to support him) -- winning the Ligue 1 Player of the Year award ... along with the Young Player of the Year.

Careful, Neymar ... Mbappe is the new hotness.

And, if you're not careful, he might skip YOUR next award ceremony when Rihanna calls him!!