Replays indicated that Villa defender Enda Stevens made no contact on Saints player Jay Rodriguez before he went down. But referee Halsey - a late replacement for the ill Chris Foy - thought otherwise and Saints skipper Rickie Lambert made no mistake from the spot for his ninth goal of the campaign.
Lambert said: "I've seen the penalty loads of times. I've had a chat with Mark (Halsey) after the game. He was adamant he was 100% right - and he has guessed. It was never a penalty, never, nowhere near it."
He added: "Was it cheating (by Rodriguez)? Listen, I'm not going to get involved in calling someone a cheat. From our point of view Mark has got it wrong. He'll be totally embarrassed by it. It is nowhere near a penalty.
"In the big moments in big games in big areas of the pitch, the referee has got to get it right. There is no point in guessing or surmising something has happened. You've got to get it right. That's where the letdown is. I'm sure when Mark watches it on TV he will be embarrassed by it."
Saints boss Nigel Adkins insists Rodriguez did not dive as his side secured their second away win of the campaign.
He said: "I've seen the video. The challenge on Jay, there is no contact. Jay's leg has moved out of the way which is just as well otherwise there would have been clear contact. We don't advocate diving at our club and we probably should have had seven or eight penalties this season we weren't given. It is a big decision. It is not a dive."
Paul Lambert took heart from his side's second-half performance, when striker Christian Benteke spurned several chances.
He said: "I can't fault them for the second half. They were relentless. We had loads of chances. They gave us everything and we've beaten by a penalty that wasn't one.
"On another day Christian scores but, to be fair to the big guy, he has pulled us out of trouble loads of times this year. You can't have a blame culture. You are in it together and win and lose together."
Source: PA
Source: PA