The world number one has been knocked out of the tournament in the third round, losing to 29th seed Alejandro Tabilo of Chile.
Novak Djokovic says he will have medical tests after being struck on the head by a metal water bottle and then suffering a shock exit at the Italian Open.
The world number one said how he felt on court on Sunday was “completely like a different player entered into my shoes. Just no rhythm, no tempo, no balance whatsoever on any shot”.
“It’s a bit concerning,” he added.
Djokovic, a 24-time grand slam champion, was beaten in round three in Rome by 26-year-old Chilean Alejandro Tabilo, who won the match 6-2 6-3 in just 67 minutes. It was one of the Serbian’s worst displays at one of his favourite tournaments.
The 36-year-old sports star was signing autographs on Friday following an earlier win when he collapsed on to the ground after the container, which fell out of a spectator’s rucksack, struck him from above.
Speaking on Sunday about the incident, Djokovic said: “It was unexpected obviously. I wasn’t even looking up. Then I felt a very strong hit in the head. That has, yeah, really impacted me a lot. Been through half an hour, an hour of nausea, dizziness, blood, a lot of different things.
“I managed to sleep okay. I had headaches. The next day was pretty fine, so I thought it’s okay. Maybe it is okay. Maybe it’s not.”
The top seed added: “I didn’t do any scans or any tests. Right now, I feel like I should do it, so I will do it and let’s see. Let’s see what’s happening.”