Hereford United director Grenville Smith feels the Bulls are playing well enough to cause an upset at Sheffield Wednesday on Saturday.
"I've been on the board for over eleven years and every game now I don't get excited I get nervous," Smith told BBC Hereford and Worcester. "The tension in my stomach watching the football is terrible.
"We've got a big game this weekend and I fancy another giant-killing act, I really do.
"We're scoring goals, we're not conceeding so many goals now, and they are conceeding goals.
"If we have a bit of luck I think we could well get through to the fifth round for the first time."