Jones admits Bradford were coasting at times during the shock win.
"Did it surprise me how badly Arsenal played? I think it did, yes. We were surprised at how comfortable we were at times. They didn’t really have too many shots on goal," he said.
Jones continued: "They tried to play too much football at times, especially down the middle. We defended really well, and our organisation and discipline were really good, which put us in good stead for going through.
"I thought we’d be up against a lot of youth players, with a bit of experience thrown in, but it was nothing like that.
"When we saw their team sheet, we couldn’t believe it. Steve Parkin (assistant manager) wrote their line-up on a piece of paper, then put on the bottom 'poor team' with an exclamation mark."