A “concerned” Novak Djokovic is set to undergo medical tests after feeling the effects of being struck on the head by a bottle in his shock exit from the Italian Open.

Djokovic was beaten 6-2 6-3 in just 67 minutes by Chile’s Alejandro Tabilo in Rome, the six-time champion committing 22 unforced errors, serving five double faults and failing to create a single break point.

The one-sided loss came two days after Djokovic collapsed to the ground after being struck by a bottle which fell from a spectator’s backpack as the world number one signed autographs following his win over Corentin Moutet.

“I think in the video you saw it very clearly,” Djokovic said after his defeat to Tabilo.

“It was a very unfortunate, unlucky situation for me. It was an accident where that guy leaned over the fence, and the bottle dropped from his rucksack and landed directly on my head.

“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.

“I mean, the way I felt on the court today was just completely like a different player entered into my shoes. Just no rhythm, no tempo, no balance whatsoever on any shot.

Novak DjokovicSerbia’s Novak Djokovic reacts during a match against Chile’s Alejandro Tabilo at the Italian Open (Alessandra Tarantino/AP)

“It’s a bit concerning. 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.”

The tone for the contest was set early on when Djokovic saved three break points in the opening game, two with aces and the third with a sublime drop shot from behind the baseline, only to serve a double fault after Tabilo created a fourth break point opportunity.

Two brilliant winners then gave Tabilo a second break for 3-0 and the 26-year-old showed no signs of nerves as he served out for the set with the minimum of fuss after just 31 minutes.

Fans expecting a determined response from Djokovic were in for a shock when he instead started the second set with consecutive double faults to lose his serve once more, the 24-time grand slam winner strangely rushing through his service games.

Tabilo continued to hold serve with ease and fittingly it was another Djokovic double fault on the first match point which sealed the biggest win of 29th seed’s career to date.

“I came on court just looking around, just trying to soak it all in, trying to process everything and now I just can’t believe it. I’m trying to wake up right now,” Tabilo said in an on-court interview broadcast on Sky Sports.

“I was just trying to keep my nerves in, keep swinging. Obviously every time you feel you’re closer to the end your arm starts to get a little tighter so I was just trying to not think about it, take it point by point and it’s crazy.

“I can’t believe what just happened.”