Djokovic struck with bottle from stands after winning Rome opener
World number one Djokovic was left crouched on the ground in pain as the bottle hit him on the back of the head as he was signing autographs for fans while he exited the centre court at the Foro Italico.
Djokovic was then led from the arena on foot by security staff who covered the 24-time Grand Slam winner while he made his way into the bowels of the stands.
In a video of the incident published by Italian media it is not clear whether the hard reusable bottle was launched deliberately from the stands or fell accidentally onto Djokovic's head.
Tournament organisers did not respond to AFP's request for an update on Djokovic's condition, but should he be OK he will face Chile's Alejandro Tabilo next as the Serb warms up for the French Open with a great chance to add to his array of titles at the Foro Italico, where only Rafael Nadal has won more with 10.
The top seed, who turns 37 a few days before Roland Garros gets underway later this month, easily won his first match since losing to Casper Ruud in the semi-finals at the Monte Carlo Masters.
Djokovic has made no secret in the past that he loves playing in Italy and with a clutch of big names either out injured or struggling he will fancy his chances of a record-extending 41st Masters 1000 crown.
The Rome tournament, which runs until May 19, is missing two of its biggest stars with Italian world number two Jannik Sinner and third-ranked Carlos Alcaraz both withdrawing from the men's draw before the start.
Meanwhile clay court icon Nadal had a creaky start in the first round against qualifier Zizou Bergs on Thursday and is on the opposite side of the draw to his great rival, meaning the only way that the pair could face each other would be in an unlikely final.
One of Djokovic's potential threats, third seed Alexander Zverev, breezed into the third round with a 6-0, 6-4 win over Australia's Aleksandar Vukic.
And it was similar story for Djokovic, who after briefly being bamboozled by flamboyant Moutet's array of shots slowly eased into gear, rattling off seven games in a row from 3-1 down in the first set to take control of the match.
Moutet briefly brought a smile to Djokovic and the crowd's faces when his phone went off in the middle of an absorbing opening game of the second set, which lasted nine minutes and saw the Frenchman save four break points before giving way and allowing Djokovic to cruise to victory.