Stewart took a tumble in the 56th minute to earn a spot kick and then dusted himself down to slot home from 12 yards to put the Jambos 2-0 up.
Frail said: "When they come from us we'll take them. But I certainly don't think it was a dive"
The assistant added that the Jambos were well worth the three points in the end: "We were pretty solid today and controlled most of the game" he said.