At £12 million, the former Wolves man appeared overpriced - before he hit the goal trail this season.
Pardew told the Sunday Sun: "Fletcher's certainly proven his worth. I thought he was a good player at Wolves and maybe the fee has given him added confidence.
"As a player, I was linked with a move and my value went from £10,000 to £200,000. That does give you a boost.
"He probably figured he was a £8m or £9m striker and a Premier League player, then suddenly he was worth a lot more. So that has given him belief. He's certainly shown that on the pitch, because you can crumble and go the other way. Fair play to him."