Alasdair Thorburn told the High Court in Dundee he had returned to his flat in Perth's High Street from a nearby pub before falling asleep in his chair. A short time later he was woken by two men entering his flat.
Mr Thorburn, 68, said accused Raymond Moir and another man, Michael McLellan, entered his flat and said: "We know you have money – tell us where it is."
Mr Thorburn said: "They tied my face with cling film or a broken plastic bag.
"They were demanding my pin – I eventually gave it to them - They smacked me about the face and stubbed a cigarette out below my eye."
Moir, of Perth, denies assaulting Mr Thorburn.
The trial continues.