He is obviously a good manager, because to do what he did at Porto proved that. However, much of his success in the Premiership is down to the fact that he can load his bench with players worth 10m, 20m or 30m and as soon as his original tactics backfire [ which has been often enough ], he can bring these world class players on which immediately changes things and results in them winning games late on. Another effect of this must als be that it has a huge effect on the morale of the Sunderlands, Birminghams, Portsmouths etc when they are holding on for a draw or a 1 goal lead and see 2 or 3 players of that calibre coming off the bench. I know it's a mute point, but I seriously doubt if they would win as many games in the Premiership if teams were limited to 1 sub like in the old days. When they come up against the higher quality sides in the CL, this doesn't seem to work as well.