Newcastle forked out a club-record fee to snare Isak away from Real Sociedad towards the end of the summer transfer window, despite him initially appearing to be out of their price range.
Isak scored on his debut at Anfield against Liverpool and had a goal disallowed against Crystal Palace last weekend.
The forward scored just six times for Real Sociedad last season and many believe it will take some time for him to adapt to the Premier League.
However, Hislop has been left pleasantly surprised at the start the Newcastle new boy has made in England.
He is of the opinion that if Isak manages to score 15 goals for Newcastle this season it will constitute a good first campaign at St. James’ Park.
The former goalkeeper told ESPN FC: “I was really pleasantly surprised by the start, the way he took his goal; I know he had one disallowed as well.
“Between now and the end of the season I think if Isak gets 15, that’s a very good return.
“I think he can.”
Newcastle are certain that they have made a smart move by investing heavily in Isak, who has the ability to grow with the club in the coming years.
