World number 33 Yulia Putintseva raised security concerns about a spectator during her first-round match at Wimbledon, asking for them to be ejected.
Early on in her match against Amanda Anisimova on court 15, the 30-year-old complained directly to the umpire about a spectator, whom she described as "crazy" and "dangerous".
A club spokesperson said the matter was "dealt with".
During a change of ends when trailing 3-0 in the opening set, Putintseva, from Kazakhstan, first voiced her concerns.
"Can you take him out, I am not going to continue playing until he leaves. These people are dangerous, they are crazy," she said.
She was then seen pointing towards an area of the crowd and described the person as wearing green.
The chair umpire came down onto the court and spoke to three members of security staff.
When Putintseva was told play would resume, she was heard saying she did not want to do so until security had handled it.
"Take him out, because maybe he has a knife," she said.
Putintseva was emotional later in the match and went on to lose 6-0 6-0 in 45 minutes.
She did not speak to the media afterwards.
A spokesperson for the All England Lawn Tennis Club (AELTC) told BBC Sport: "Following a complaint about the behaviour of a spectator at the match on court 15, the chair umpire informed security and the matter was dealt with."
Anisimova, meanwhile, told the BBC she believed the spectator had been saying something "when [Putintseva] was about to serve" and added: "I am sure that we were protected".
Earlier, AELTC chief executive Sally Bolton said on the subject of security: "We're well-versed in the measures that need to be put in place so players can go about playing here in the confidence they're being well looked after."