I wouldn’t say it’s one of Celtic’s best ever sides. Their teams under Martin O’Neill with the likes of Larsson, Sutton, Petrov were better than this current side.
However I don’t think the gap in quality between Celtic and sides like us has ever been bigger, even back in the O’Neill days.
What makes this Celtic side so strong is their workrate, athleticism and intensity. When you have all of that along with the best players in the league then you will make short shrift of most sides nine times out of ten.