Roger Federer admitted on Sunday that a bizarre online death threat had been a distraction in the build-up to the Shanghai Masters but said he was now focusing on action on the court.
Tournament officials gave assurances on players' security after hate messages from a blogger, who calls himself 'Blue Cat Polytheistic Religion Founder 07' appeared on the popular baidu.com site.
"On October 6, I plan to assassinate Federer for the purpose of tennis extermination," read the message.
The user also posted a doctored image showing a decapitated Federer on his knees on a tennis court, with an axe-wielding executioner posing next to him.
Federer, speaking at a press conference on the first day of the tournament with black-suited security personnel looking on, said the run-up to the Shanghai Masters had been different from usual.
"Obviously maybe it's a little bit of a distraction, there's no doubt about it. But you have to be aware of what's happening around you," he said.
"But that is the case anyway anywhere I go today with my fame and all that stuff."
The 17-time Grand Slam champion, who has a first-round bye, said he first became aware of the issue about 10 days ago, before it hit the headlines. But he said had felt safe in China and praised the authorities.
"So then obviously it came out in the press. That's when things changed. It became much more public, which I'm a bit disappointed about, that it did come out in the press," he said.
"It was something just very small on a website, nothing clear and concrete, people just debating. That it makes that big news is a bit surprising to me."
Federer's wife and twin daughters have not travelled to China but Federer said that decision had nothing to do with the threats, adding: "It was a last-minute decision for me to come here in the first place."
The Swiss maestro, 31, who returned to the number one ranking after his Wimbledon triumph in July, said he felt "fine" after some time off and was hoping to finish the year in top spot. But it was not his overriding goal.
"For me I've already reached my goal by getting back to world number one in the summer. That was for me the goal, getting back there and winning a Grand Slam, particularly Wimbledon."
Federer and Novak Djokovic are the top draws in the teeming Chinese city, along with Britain's defending champion Andy Murray, fresh from his US Open success.
Federer missed the 2011 Shanghai Masters but has an enviable record at the magnolia-shaped Qi Zhong Stadium, winning two of his six season-ending showpiece titles there before the event shifted to London.
As the gruelling season enters its final few weeks, the Swiss, as of Sunday, had 11,805 points in the rolling 12-month rankings with Djokovic second on 10,470. A total of 1,000 points are on offer to the winner in Shanghai.
But crucially the Serb has fewer points to defend for the rest of the season, and his eye is firmly on supplanting Federer by the end of the year.