Goals from Jordan Rhodes and Danny Murphy cancelled out Lee Novak's opener but the same player pounced to earn a point for Huddersfield in the fifth minute of stoppage time.
"I think over the course of the game it was probably a fair result. We were up against a good team tonight with some good players," said Grayson.
"We competed well, we were a little scrappy at times with possession of the ball, worked hard, put them under pressure, got the goal.
"But you always know you're going to be up against it at times with the players they've got in their squad.
"It was inevitable Jordan (Rhodes) was going to get on the end of a chance to score.
"There was a major decision, which made us go 2-1 down but the players reacted in a real positive manner and kept going until then end.
"I think we justifiably got out just rewards at the end of it."