“His game has come on this season again, into being a really effective player because he has got that ability.
“James is technically very good, one of the best receivers of the ball I have ever worked with, in how he takes the ball on the side of the field or in the middle.
“He has a wonderful touch and how he can move it with his second touch and now he is adding goals to his game.
“He has that hunger to score goals and all three of them were outstanding. He was the class player on the pitch and thoroughly deserves the matchball.”
Forrest added: “I am absolutely delighted and getting into the next round as well, it was a good day all round.
“I have been on two goals before and had a couple of chances, but not managed to get a hat-trick so I was delighted to get it.”
Thistle boss Alan Archibald bemoaned his side’s slow start to the match.
He said: “There are positives to take from it, if you get the first 15 minutes out of my head. It was a terrible first 15 minutes start to the game.
“We can’t start any game like that, especially here, which was a big disappointment, but the guys showed great character to come back from that.”