Dugarry turned in what Saints boss Gordon Strachan described as 'a world-class performance' in the 3-2 win that all but guarantee's Blues' top-flight status for another season.
"There has not been a better player ever to play for this club," Bruce said after the game.
"He could play in any team in the world he wanted to and we are delighted to have him.
"He came here in January and knew it was not going to be easy but he rolled up his sleeves and has led from the front.
"Some of the comments that were said when he came here, most notably by Ray Houghton, were scandalous, and maybe he has shut those people up."