Wolves won on goals by Nenad Milijas and Kevin Doyle for its fifth win of the season.
McCarthy was greeted by chants of "Super Mick" when it walked off the field at Molineux.
Earlier in the week, Hahnemann backed McCarthy's move: "Mick put out a team out with six internationals in it. Are the Premier League saying Michael Mancienne of Chelsea is not good enough? I certainly wouldn't want to say that to him. Kevin Foley was Wolves' player of the season last season. Matt Hill has played nearly 400 competitive games. Stefan Maierhofer has played up front for Austria and Roland Zubar is a great talent from France. It's disrespectful to suggest the guys who played weren't up to it. What do the Premier League do about the fact we've got five games in two weeks?"
Wolves has won three of its last four games, all with Hahnemann in goal, to get out of the relegation zone.