The group knocked on the victim's door at the property in Dixon Avenue before forcing him to hand over cash.
It is understood the man, who is in his 40s, was followed home from the local shops before the robbery.
He is believed to have been targeted by three men and a woman.
They were described as Eastern European.
Police have launched an investigation and a hunt is under way to find the culprits.
It is not known how much money was stolen in the incident.
A Police Scotland spokeswoman said: "The Robbery Unit at Pollok Police Office are investigating a robbery within a flat in Dixon Avenue.
"Officers were called to a report of a man being robbed at 1.30pm on Thursday. Inquiries are continuing."
The incident comes after the Evening Times revealed two young women robbed a frail pensioner of £2000 after he left a bank in Govanhill.
John McCort was thrown against a wall in Calder Street during the daylight attack.
The 74-year-old was so shocked he didn't report the mugging to police for several days.
It happened on Tuesday May 27, shortly before 10am, but wasn't reported to police until Friday, May 30.
The women who robbed Mr McCort were described by a police source as Eastern European.
There is nothing to suggest the incidents are linked.
Meanwhile, investigations are continuing into a sexual assault in Dixon Avenue in February and rape in Dixon Road last month.
Senior detectives said additional patrols had been provided in areas of the city and vowed to snare those responsible.
More than 5000 women, men and children attended a rally in a peaceful protest at the incident.
Banners and chanting were not allowed but some had slogans written on their clothes.
Anyone with information is asked to call Police Scotland on 101.