The Tigers had looked to be facing defeat following Jason Scotland's goal but Simpson - making his first appearance since January - nodded home Corry Evans' centre to extend his team's unbeaten run to eight league outings.
It marked a dramatic return to first-team action for the former Arsenal man, who has struggled to feature under Pearson following the transfer-window arrivals of Matty Fryatt and Aaron Maclean.
But it was the summer signing who earned the plaudits from Pearson, who said: "It was a clever header for the goal, with his back to goal. He had a lot to do, to manipulate the ball like that.
"Jay's had a frustrating time. He's been out of the side and it was a good response for him. `He's had to be patient and probably feels he hasn't had a fair crack of the whip, but it illustrates that you need a squad ethic to be successful.
"If you aspire to succeed you need a group of players who are prepared to play for each other and we've certainly got that."