The Irishman scored two sweet strikes and also laid on a goal for Callum Robinson as he put in his best performance for the Lilywhites to date.
Daryl Horgan also got his first goal for the club as PNE ended a run of six straight defeats against Brentford and avenged the 5-0 defeat at Griffin Park back in September.
“Everybody knows Aiden’s quality and what he’s got,” said Grayson.
“He can use both feet, go past defenders and he can shoot from distance.
“Sometimes it doesn’t go your way but sometimes you get a day like today when everything you hit is a sweet connection and gives the goalkeeper no chance.
“They’re two great goals, he’s set Callum Robinson up for the crucial goal just after half-time.
“Aiden’s got fantastic quality, we’ve seen that all season he’s been here and just not seen the end product sometimes.
“He’s enjoying his football and we’re reaping the rewards.”
It was a day of firsts for North End, who hadn’t come from behind to win this campaign or scored four goals in a game.
“People talked leading up to the game about the record we’ve got against Brentford,” said Grayson, whose side won for the first time in five Championship games.
“But records are there to be broken.
“They’d had two strong performances against Aston Villa and Brighton and we were disappointed when we went a goal down from the set piece.
“But over the course of the game we grew.
“We did things better on the ball and off the ball and ultimately we’re delighted to have won the game 4-2 and with the chances we could have had a few more.”