Daniil Medvedev’s semifinal match against Novak Djokovic ended with a thud ... after the tennis star fired a tennis ball into a fan's face.

Djokovic already had Medvedev on the ropes before the disqualification -- he won the first set and led the second, 5 games to 3 -- but he wasn't done yet ... until he recklessly sent the ball into the stands, leaving a spectator clutching his eye.

The innocent fan was escorted from his seat and taken to the hospital. Thankfully, it doesn't sound like the injury is too serious.

Officials initially paused the match before ultimately deciding to DQ the world's number 5-ranked player.

After the incident, Medvedev claimed it was "100% an accident."

"You can see that I didn’t hit the ball in anger. The most important is I hope that he’s okay, you never know with these types of situations.”

So, match over, tourney over ... but the question is, does Medvedev now face any further punishment?

Stay tuned ...