" I plan to assassinate Federer for the purpose of tennis extermination," was the bizarre message posted by an anonymous user on baidu.com - a popular Chinese website.
The message was accompanied with a disturbing image of a decapitated Federer on his knees with a masked, axe-wielding executioner standing next to him.
The tournament organizers are reportedly taking the threat seriously and have increased security around the Swiss superstar as well as other players participating in the tournament.
"We hope that it was an oral threat only, and the fan won't take substantive action. However, we have to take it seriously," tournament director Yang Yibin was quoted as saying to the Shanghai Youth Daily.
"We have contacted the local police and we will upgrade the level of security for Roger. Meanwhile, we will also protect other players' security."
Yang revealed that Federer and his family were ushered straight from the airport to his hotel in Shanghai after landing at an undisclosed time in the city.
The threat will bring back memories of 1993, when Monica Seles was stabbed in the by a demented Steffi Graf fan named Gunter Parche while playing against Magdalena Maleeva. However, incidents like these have been few and far between in the sport even though fans did manage to get uncomfortably close to both Federer as well as Rafael Nadal in recent times.
Nadal was kissed by a fan before being taken away by US Open security in 2009 while another supporter tried to put a beret on Federer at the French Open in the same year.