Not many games have they played under him therefore it's not worth saying that Manchester United haven't gotten a lost under hime. He has played only 2 or three games. After playing as many as 5 game, he would have conceded defeat. But unfortunately he won't be handling the team after the next game. The main new coach will be taking over.
It's true. With only two matches so far, it's hard to say Manchester United are improving and Nistelrooy is a good coach. He shows some signal of being a good coach in future, but now he has many things to do, more time, more matches to prove his management capability. Manchester United will be coached by Ruben Amorim, not Nistelrooy in future so Ruud van Nistelrooy can enjoy his short time as a head coach for Manchester United. He might have another chance to be Manchester United head coach officially, not as a temporary replacement.