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Wrexham beat the bottom of the table Lilywhites 4-1 at The Racecourse to move up to 14th place in the Championship with O'Hare was at the heart of much of Wrexham's attacking play.
The 28-year-old went close to scoring on several occasions, only to be denied a breakthrough Parkinson felt he richly deserved.
"I thought his all-round performance was a very high level," said Parkinson.
"He scrapped and he fought because at times it was a scrappy feel to the game because we came up against a team who were fighting for everything and you could see that in the way Grezer (Preston boss Graham Alexander) set them up.
"Callum did that part of it but then showed real quality.
"He's had two or three moments there where how the ball hasn't gone in, I don't know."
Brought in from Championship rivals Sheffield United for an undisclosed fee on deadline day in the summer transfer window, O'Hare is still waiting to open his Wrexham account after six starts and one substitute appearance in the league.
But Parkinson has been encouraged by his influence in the final third and says it is only a matter of time before a goal arrives if he maintains his current approach.
"While he's waiting for that goal, keep playing like that," he added.
"Don't let it affect you and he won't because he's a tough character and his performances have been good since he's been here.
"The one thing about Callum is he's always in around the box, he's always creating stuff, he's a nuisance and he showed that."
O'Hare's next chance to get off the mark will be on Saturday when Wrexham face Blackburn Rovers at Ewood Park.
Rovers are 10th in the table, one point ahead of the Reds, but they lost 3-2 away to West Brom on Saturday.