Ronnie O'Sullivan gave the returning Crucible fans a treat by firing three consecutive centuries to wrap up a first round win over Mark Joyce - but fears their overenthusiasm could wreck his bid for a seventh-world crown.
O'Sullivan revealed he was accosted on Saturday in a "nightmare" incident at a city centre restaurant, and will now cut back his appearances in public in order to minimise the risk of being forced to withdraw due to a positive test later in the tournament.
The world number two and top seed was having lunch and a coffee with friends in between Saturday's morning and evening sessions when the incident happened.
"I knew it would happen if it got busy," O'Sullivan said. "What can you do? People don't think, do they? I was harassed like you wouldn't believe it. The geezer's come up to me, I was like: 'Please, I have to get through this tournament Covid-free. I beg you.'
"It's getting busier. The geezer was a nightmare. The guy at the restaurant came out with his two staff members, they got him away.
"It's no-one's fault. People have been let out and are out shopping. It's the way it is. Last year it was different and it is different this year. It was so much quieter; you could sit outside last year and have a meal.
"Most people are fed up with these lockdowns and want to leave their lives now. It was one or two. It's the way it is. If I didn't have to be clean for this tournament, it wouldn't matter so much, but if I get Covid I cannot play.
"I have to stay away. I will find places to go where it is a little bit quieter if I can. I will come in at the last minute, stay away from Sheffield as much as I can."
O'Sullivan, who said that two members of the restaurant's staff had been forced to intervene, added: "Ninety-nine per cent of the people are fine but it's just the odd one who was a bit boozed up and having a mental one. It was so busy and this geezer was a nightmare.
"He was p***ed up and coming at me and I was like, 'mate, please.' What can you do? I've got to stay indoors and stay away.
"If I didn't have to be clean for this tournament it wouldn't matter, but if I reached the quarter-finals it would be a sickener to have to pull out. As a sportsman I can't work if I get ill so that's my only problem."
Nevertheless, O'Sullivan hailed the return of fans to the famous venue, which was filled to 33 per cent capacity as part of a pilot scheme surrounding the return of fans to sporting events, after turning on the style to claim a 10-4 win.
Despite establishing a 6-3 lead O'Sullivan has struggled in an error-strewn opening session, but ended it by becoming only the eighth player to make three consecutive Crucible centuries as breaks of 124, 137 and 112 finally saw him ease over the line.
O'Sullivan added: "It was great to have the crowd in there, they miss their snooker and I probably would have given up mentally in that match if there was no crowd there.
"I'd have thought, I'll get out of here and go home and do a bit of punditry, but because the crowd are here you feel you've got to perform because they've paid their money and come out to watch.
"When I think back to my great matches and you see the crowd's faces and the pleasure that you give them when you play an unbelievable performance, that sticks in your mind that that's what I'm here to do."
With sanitiser stations provided around the venue, fans had their tickets scanned before sitting in designated seats, socially distanced.
World Snooker Tour confirmed it had issued written advice to players prior to the tournament to "be careful" when they are in public areas.
Former semi-finalist David Gilbert emulated O'Sullivan in also making three centuries as he established a 7-2 overnight advantage over qualifier Chris Wakelin.