McManaman clattered knee-high into Massadio Haidara, who was subsequently carried off on a stretcher with suspected ligament damage, but the youngster escaped punishment in the first half of the Latics' vital 2-1 win.
"It is an awful challenge. The pictures speak for themselves," said Pardew. "I thought it was a bad challenge and I was 60 yards from the incident. The players knew because they were on top of it and there was a lot of bad feeling about that incident when it goes unpunished."
He went on: "He (Halsey) said 'If I've missed it I apologise' - that was at half-time.
"If it goes unpunished it doubles the impact on the mentality of the players and the team and it did have an impact on us, you can't get away from that. My job was to calm the players at half-time, not go looking for retribution, and try to win the second half - which to all intents and purposes we did."
To add insult to considerable injury, Arouna Kone's 90th-minute winner - after Davide Santon had cancelled out Jean Beausejour's first-half opener for the hosts - appeared to come off Maynor Figueroa's hand in the build-up.
"But again there's a decision at the end where we should have had a corner, it goes up the other end and there's a handball - that is tough to take," said Pardew. "The linesman is looking right at it, the referee is there and all our players reacted and in that split second we didn't clear the ball - that's what happens when you miss a decision as big as that."
Wigan manager Roberto Martinez defended McManaman and his team and does not think the striker will be retrospectively punished.
"Remember Callum McManaman was making his full debut in the Premier League and, as a young man, you know you are going to give your life for everything," said the Latics boss. I haven't seen it but I believe he gets the ball and then it's a bad challenge.
"No-one wants to see that but I guarantee that is just a striker trying to win the ball over-enthusiastically because he is making his (full league) debut. What you need to look at in those incidents is if there is intention, a nastiness about the tackle. We are not a nasty team. He has not a nasty bone and is not bad-intentioned."
- Sports & Recreation