The 31-year struck nine minutes from time to claim just the Magpies' second Barclays Premier League win in eight attempts with the game seemingly heading for stalemate.
Pardew, whose decision to replace Papiss Cisse with Ameobi 20 minutes earlier had been booed by a section of the 50,180-strong crowd at St James' Park, said: "I know the crowd weren't particularly pleased when I took Cisse, a goalscorer, off but I just felt Shola, he's a big man and this was a big occasion and he likes big occasions."
He went on: "It said QPR on the programme but really it was bigger than that, I think we all knew that and he has that calm head - he knows what is demanded here - to produce a quality goal, and it won us the game.
"I wanted to get Shola on the pitch, and thank goodness I did because it was a really class finish. He could have taken the shot with his right foot, which is his stronger foot, but to have that composure in that area is first-class."
Pardew had admitted before the game that he would not enjoy his Christmas lunch unless he sat down with three points safely banked, and he was delighted to be able to do so ahead of a tough Boxing Day trip to Manchester United.
He said: "The pudding will taste a little bit sweeter. I feel sorry for our fans. We have put them through the rack, really, over this last period.
"They have watched some football that hasn't been our best. But you have periods in your tenure as a manager and sometimes a season."
He said: "I thought we were going to hang on and nick a draw. I couldn't see us winning, but we just couldn't see it through. I thought we could hang on for a good point to keep us going, but it just wasn't to be."