Japan’s Kei Nishikori said Friday it would be “a shame and no fun” if his home Olympics takes place without spectators.
Tokyo organizers marked the 50 days to go landmark Thursday by insisting “100 percent” the Games will go ahead.
“The biggest challenge will be how we can control and manage the flow of people,” said Tokyo 2020 president Seiko Hashimoto.
“If an outbreak should happen during the Games times that amounts to a crisis or an emergency situation then I believe we must be prepared to have these Games without any spectators.”
Nishikori said he desperately wants to see the Games take place with fans.
“I will be really happy to play on the court, but I’m really guessing right now it’s going to be really tough with spectators with this situation,” the 31-year-old said at the French Open on Friday.
“Without anyone on the court, just the team members, that’s not going to be fun for me, and you don’t feel like playing the Olympics in your home country.
“So that’s the only thing giving me a little bit of shame if there is no one watching. But we’ll see what they’re going to say.”
World number one Novak Djokovic has already said he would reconsider taking part in the Tokyo Olympics if spectators were banned from attending.
“I’m planning to play Olympic Games for now. As I heard, there’s going to be some crowd, local crowd from Japan only,” said Djokovic earlier this week.
“As I understand, 20 percent, 30 percent of the capacity. If they change something, if there’s not going to be any crowd, then I’ll consider if I want to go or not.”
Nishikori, meanwhile, reached the French Open last 16 for the seventh time when Swiss opponent Henri Laaksonen retired with a leg injury in their third round clash.
Nishikori, ranked 49, had taken the first set 7-5 when the Swiss qualifier quit.
The 31-year-old Japanese star had needed more than eight hours and two five-setters to get to the third round.
On Friday, however, he was on court for just under 60 minutes and goes on to meet German sixth seed Alexander Zverev for a place in the quarter-finals.
Victory over Zverev on Sunday would give him his 100th match win at the Slams.
Zverev has a 4-1 winning record over Nishikori including two wins on clay this year in the build-up to the French Open in Madrid and Rome.
It was a disappointing end to the tournament for 29-year-old Laaksonen who was playing in the third round of a Slam for the first time having come through qualifying.
The six matches had taken their toll.
“If I would say before the tournament that I reach third round, I would take it every time,” said the world number 150.
“With an injury it’s always tricky. You fall into a vicious circle. You have one problem, then the next one comes.
“I was doing my best. This was the maximum now here.