Despite being at the center of a massive COVID-19 exposure, tennis superstar Novak Djokovic is still refusing to wear a mask!

The 33-year-old Serbian was spotted out Wednesday in Marbella, Spain -- a super popular vacation spot -- hanging out with a bunch of people.

No one in Novak's group appeared to be wearing a face-covering or seemed to make an effort to social distance.

Of course, Spain was hit particularly hard by the coronavirus -- with over 28,000 reported deaths -- but the popular beach areas finally began opening up earlier this month.

In fact, there are 3,000 "beach wardens" patrolling the sand to enforce safety protocols -- including mask-wearing.

There are stiff penalties for non-compliance -- including a $110 fine if caught maskless.

Obviously, Novak can afford a measly fine -- you'd think he'd want to avoid the public shaming (AGAIN) after throwing that COVID-infested tennis tournament last month.

As we previously reported, Novak blew off social distancing advice and hosted a tennis tournament in Croatia -- and shocker -- a bunch of people tested positive!

Both Novak and his wife contracted the virus -- and while they eventually recovered, you'd think they'd start taking safety measures more seriously.