The spot kicks, converted by Willian, were awarded after a Nelson Semedo challenge on Tom Cairney and a late Joao Gomes challenge on Harry Wilson, the latter given after a VAR review.

"I've always been for VAR, but I think it's causing a big problem at the moment," O'Neil told reporters.

"The fact that the first one isn't deemed a clear and obvious error and the second one is, I just think VAR has cost us there.

"Maybe tonight has finally turned me against VAR when I thought it would help, but it doesn’t.

"The referee basically admitted they made a mistake with the Nelson one, but the one with Harry Wilson, we disagree a little bit."

Wolves are 12th in the Premier League with 15 points from 13 games but O'Neil said "bad refereeing decisions" had cost them another seven points.

"I'm managing a big football club here and the difference that you're making to my reputation, to the club's progression up the league, to people's livelihoods, it's huge," he added.

"It can't be like this with all the technology and all the time in the biggest league in the world that we're getting so many wrong. It can't be ok."

O'Neil is the latest Premier League manager to hit out at VAR, with Liverpool's Jurgen Klopp, Tottenham Hotspur's Ange Postecoglou, Chelsea's Mauricio Pochettino and Arsenal's Mikel Arteta among those criticizing the system.

English referees body PGMOL has admitted some mistakes but also recommended a more proactive VAR involvement during games.