Mourinho has seen his Manchester United side win five of their opening six games of the Premier League campaign.
In games against West Ham, Swansea and yesterday against Everton, the Red Devils have scored at least two goals inside the final 10 minutes of the match to go on to win 4-0.
Forward Anthony Martial has benefited from their late scoring, with his three goals this season coming in the closing minutes as a substitute.
But Robson says success comes from wearing teams down throughout the game rather than the substitutions.
“No, I think it’s the team,” Robson said on ESPN FC.
“In any game of football, you have to earn the right to play.
“To have to dominate the opposition, sometimes that will take you five minutes and win the game comfortably, sometimes it will take you 70, 80 minutes to get on top of the opposition.
“What the substitutes are seeing the benefits of is Manchester United eventually dominating the opposition.
“They’re tired, they’re struggling to hold on and Manchester United’s subs are coming on and having an impact.
“Whether it be Martial, whether it be Fellaini, whether it be Rashford at times.
“All these sorts of players are having an impact when they come on, not because of the tactical changes Jose Mourinho is making.”
United are back in action against Burton Albion in the Carabao Cup on Wednesday (8pm).
