Ryan Stoker went to the 73-year-old victim's home in Sunderland on December 23 2020 and borrowed £40 then returned on December 24 to get £40 more.
Newcastle Crown Court heard the pensioner had agreed to help because the 32-year-old conman claimed his aunt lived over the road and that all of the cash machines in the area were broken.
She had been reluctant to hand over any money during his second visit but Stoker's behaviour made her "scared" and she gave him the cash so he would leave.
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The court heard the formerly active pensioner, who would make craft items to sell for charity, was so affected by what Stoker did that she moved out of her home and into sheltered accommodation and has since suffered a stroke.
Prosecutor Neil Jones told the court Stoker's offending was exposed when the victim visited her sister on December 30, 2020, where she "wasn't her normal self" and told her sibling "I've done something stupid".
When the pensioner told her sister exactly what had happened the police were called.
Mr Jones said: "On December 23 2020 the defendant knocked on her door and when she answered he asked if he could use her phone to ring for a taxi.
"He told her his aunt lived across the road.
"She let him in an permitted him to use her telephone to ring a taxi.
"He then asked her to lend him £40 for a taxi to South Shields because, he said, the cash machines were not working.
"She gave him the money and he left her house."
The court heard when Stoker returned the following day, which was Christmas Eve, the victim was reluctant to hand over any more money.
Mr Jones said: "He asked to borrow another £40 in cash because the cash machines, he said, were still not working.
"She told him she did not have any money in the house, at which point he became agitated and then she became scared, so in order to get him out she gave him the £40."
The victim's sister said in a statement, which was read in court: "Before this she was independent and was out most days, on her own or with family.
"She enjoyed getting involved with charities and making crafts to sell.
"She had lived at that address around 13 years, initially with her husband, who died some years ago.
"She had loved her house and has fond memories of living there.
"She was made to feel uncomfortable at home and is now in sheltered accommodation. She should have been able to remain in her own home and would have done so had it not been for the person responsible for this deliberately targeting someone vulnerable.
"She suffered a stroke following the incident. The hospital said stress from the incident was likely to have contributed to the cause of that."
Mr Jones said there was no evidence to conclude that the stroke was directly caused by the offences.
Stoker, of Brockley Street, Sunderland, who has 60 previous convictions and has committed similar offences, admitted two charges of fraud by false representation.
Sam Faulks, defending, said Stoker had been on a "downward spiral" following the death of his father.
Judge Amanda Rippon deferred sentence until October and said Stoker has to try his best to find work and save up compensation in the meantime.
The judge told him: "This is a disgraceful offence, just before Christmas, during a pandemic.
"You targeted an extremely vulnerable lady who shortly after had a stroke.
"You caused her stress and distress, just before Christmas.
"It is disgusting what you did."
The judge said if Stoker does not attempt to get work, save money or stay out of trouble over the next four months "to prison you will go".