Narendra Patel, 61, who runs Sherborne News in South West England's Wiltshire county, was threatened by the robber wielding a seven-inch blade.
But Patel grabbed a golf club "to protect" himself and made the cowardly crook flee the store empty-handed, Mirror online reported on Monday.
"I was ready with the golf club and he just pulled back and ran. I was okay, but in that moment I was just blank," said Patel, who gave credit to his "natural reflex" for his brave act.
The robber was later identified as Damien Bendall, 25, who surrendered to police.
Bendall came into the shop and lurked suspiciously in Patel's store before pulling out the knife.
"He said nothing at all. He just showed the knife and expected me to hand over some money," Patel was quoted as saying.
The robber has been sentenced to three years in prison.