Novak Djokovic's shock exit from the Italian Open on Sunday could prove to be a decisive moment in the race for the world No 1 spot, as the top-ranked Serb prepares for his French Open title defence with Jannik Sinner poised to leapfrog him.
Two days after accidentally being hit on the head by a water bottle while signing autographs in Rome, an off-colour Djokovic crashed to his earliest defeat in the tournament he has won six times after a 6-2 6-3 third-round thrashing by Alejandro Tabilo.
Djokovic will remain 1 090 points ahead of Sinner before the year's second Grand Slam begins on May 26, but the 36-year-old is on shaky ground as he will be defending 2 000 points in Paris and winning the title may not be enough to stay on top.
"It was a very unfortunate, unlucky situation ... that guy leaned over the fence, and the bottle dropped from his rucksack and landed on my head," Djokovic said, reflecting on the freak accident that hurt his chances to pull away from Sinner.
"It was unexpected. I wasn't even looking up. Then I felt a very strong hit in the head. That has really impacted me. After that I got the medical care. Been through half-an-hour, an hour of nausea, dizziness, blood, a lot of different things.
"I managed to sleep okay. I had headaches. Yesterday was fine, so I thought it's okay. Maybe it's okay. Maybe it's not.
"The way I felt on the court was just completely like a different player entered into my shoes. No rhythm, no tempo, no balance whatsoever on any shot. It's a bit concerning."
With only six matches on clay, Djokovic will be slightly undercooked as he heads to Paris in search of a record 25th Grand Slam title.
Even if Djokovic goes on to win at Roland Garros, Sinner could rise to world No 1 for the first time on June 10 by reaching the championship match.
The 22-year-old Sinner, who skipped Rome with a hip injury sustained in Madrid, will be defending only 45 points in Paris but faces a race against time to be fully fit.
Djokovic had endured a bumpy season even before the bottle incident as the Serb's bid for a record-extending 11th title at the Australian Open was snuffed out by eventual champion Sinner in the semifinals.
He then fell to lucky loser Luca Nardi in the Indian Wells third round before being outlasted by Casper Ruud in the Monte Carlo semifinals, sparking fear among fans that his aura of invincibility was slowly fading.
Despite winning three out of the four Grand Slams last year, Djokovic split with long-time coach Goran Ivanisevic and fitness coach Marco Panichi in a bid to rediscover his best form ahead of Roland Garros, Wimbledon and the Paris Olympics.
Talk of terminal decline may still be premature and Djokovic could silence critics by winning a fourth title at the claycourt major, but he admitted things must improve fast after reaching May without a trophy for the first time since 2018.
"Everything needs to be better in order for me to have at least a chance to win it," said Djokovic.