It happened in the 400 block of Upper Gulph Road in the Gulph Mills section of Upper Merion Township.
Action News conducted an exclusive interview with the victim Monday night.
The victim, 83-year-old Joseph Petrellis, is bloodied and bruised.
"It was the most unbelievable experience I've ever had in my life," Petrellis said.
17 stitches and a swollen eye are the results of a home invasion that took place Monday afternoon.
"I very seldom open the door without knowing the person on the other side of that door. I made a very big mistake. Before you know, the gun was in my face," Petrellis said.
Petrellis says as he struggled with the one thief, another backed a car into his driveway and came into the house.
"He sees I was knocking the hell out of the guy and he ran into the kitchen and says to the guy, 'we're getting out of here, let's get out of here.' I don't know if he said don't shoot him," Petrellis said.
"That wouldn't surprise me about Joe; he's a feisty old guy," neighbor Len Marinaccio said.
Neighbors say the broad daylight home invasion in this tony enclave is unnerving.
Petrellis says the thieves got away with some cash and a diamond ring.
While he has a lot of fight, he's upset with himself for one costly mistake.
"I never in 20 years living here, I never ever opened that door without knowing the person outside that door. I've never done that. Today was the only time I've done that in 20 years," Petrellis said.
Petrellis says the suspects got away in a black 4-door car, possibly a Toyota, with tinted windows, chrome wheels and no license plate.