Tennis: Novak Djokovic requires medical attention after being struck accidentally by water bottle

World No.1 Novak Djokovic has required medical attention after being struck in the head by a water bottle following his second-round win against France's Corentin Moutet at the Italian Open.

The Serbian was signing autographs after his easy 6-3 6-1 victory against the lucky loser, when he was hit in the head by the bottle and he immediately clutched his head, as fell to his knees.

He remained crouched on the ground for several seconds, as staff ran to his aid, and was eventually helped off court. Tournament organisers said there was no cause for concern over his condition.

"Novak Djokovic on leaving the Central Court at the end of his match was hit on the head by a water bottle, while signing autographs (for) spectators," the tournament said on social media.

"He underwent appropriate medication and has already left the Foro Italico to return to his hotel."

Djokovic has taken to social media to confirm he's unharmed.

"Thank you for the messages of concern," he tweeted. "This was an accident and I am fine resting at the hotel with an ice pack.

"See you all on Sunday."

Footage posted to social media showed the bottle had slipped out of a fan's backpack and hit him. Reuters was not immediately able to independently verify the footage.

The ATP did not immediately respond to a request for comment.