Knight has been a revelation since the Scot's arrival at the club.
"When I arrived in January I had all these people telling me he was playing indifferently," Coyle told the Bolton News.
"But he has shown such quality since I have been here, he has a manager who believes in him, and I thought he was outstanding against Manchester United.
"As well as the goal, his whole performance was outstanding. He's stood there like a tower and dealt with everything that has came his way."