The second-best men's player in the world took the court Thursday to take on Alexander Zverev during the BNP Paribas Open at Indian Wells, but ended up contending more with a cloud of the dastardly drones when the match was tied 1-1.

Check out the video ... Alcaraz tries to simply swat a few of the irksome creatures away from his face before realizing his bug problem's a whole lot bigger than he thought.

CA keeps his cool for a bit while the sideline official explains the situation to the audience ... but the bees buzzing around his head proves to be too much for the Spanish star.

Carlos starts swinging his racquet around wildly before running toward the tunnel away from the court. He also pulled up his shirt over his face to protect himself -- and let's just say, it was quite a sight ... like something out of "Sleepy Hollow."

In the end, it sounds like Carlos took some damage from all this -- his agent says he got stung on the forehead during the melee, although it's unclear to what extent he was hurt.

Ultimately, it seems like everyone ended up relatively OK ... 'cause play continued just after 5 PM PT with Carlos soldiering through his injury -- after a totally unprotected individual went around and vacuumed up the insect swarm on the camera, all by themselves. Bold!