Novak Djokovic (36) was hit on the head by a bottle after his success in the second round of the Rome Masters and collapsed in pain.
Whether it was a deliberate throw of the hard plastic or metal bottle at Djokovic or an unfortunate coincidence remains unclear.
The Serb was taken out of the arena by security staff and there was initially no information about the condition of the world number one.
A video showing the incident quickly went viral on social media. Djokovic had been signing autographs after his 6-3, 6-1 win over Frenchman Corentin Moutet (25) when he was hit by the bottle from a height.
He immediately held his head, went to his knees and finally fell to the ground and dropped the pen he had been using to sign autographs. Numerous security staff and helpers quickly rushed to Djokovic to shield and protect him.
