Upon his return to Old Trafford on Wednesday night, Mourinho's Spurs were outplayed in a 2-1 loss.
And speaking after the game, Mourinho said it was easier for United to play counterattacking football against better teams.
"For the way they play it is easier for them. They are not afraid to have a defensive approach.
"It is easier for them against better teams, against teams who want more of the ball."