Ten Hag and Ronaldo butted heads in his first season in charge which eventually saw the Portuguese great released ahead of him signing for Saudi Arabia's Al Nassr.
McClaren was on United's staff at the time and told the Telegraph: “I couldn’t fault his (Ten Hag’s) approach.
“He really handled it very well. I said at the time he was the right man to go in. That was shown in the way he handled (the departure of Cristiano) Ronaldo.
"(Ten Hag) came in with set standards. Set rules. Set way of playing. And if you didn’t run, you didn’t play. He was rigid on that. Which the Dutch are. He knew that was what was needed. There could be no flexibility, no way the players could manoeuvre (out of that responsibility).
“This is what you had to do – or you didn’t play. And he took on Ronaldo, and quite rightly. Other managers have tried to adapt. Erik didn’t feel it was necessary to do that. (Ralf) Rangnick had tried and it hadn’t quite worked out and Ole (Gunnar Solskjaer) the same. So (Ten Hag) stuck to his guns and developed other players.
“That was the key thing. He was not afraid to throw youngsters in. On instances like lateness for meetings (that) was well documented, the Wolves one, (when Marcus Rashford) was a minute or two late for a meeting on game day. He (Ten Hag) put him on the bench. Granted he put him (Rashford) on and he scored the winner.
"Things like that were important. Discipline was important. Standards were important. Behaviour was important. Everybody knows that about United. That’s what he (Ten Hag) brought. Some people didn’t like that – that’s normal – but he never swayed from it. That’s his strength.”