Last updated on 57 minutes ago.
He says he has been prevented from taking bigger steps at United.
The interim boss says disruptions caused by Covid-19 have affected his progress.
The German has been perfect in four games since taking over from Solskjaer.
The Covid outbreak that led to the closing of the club's training base and the postponement of two games has complicated his work.
When asked if he had achieved his targets, he said "of course not".
Every coach wants to take faster steps and larger steps forward, and there's no difference between other coaches and myself in that area.
You need to be able to train in order to do that.
The Man Utd performance was not something that he liked.
After beating Crystal Palace and Norwich in the first three matches of the season, games at Brentford and at home to Brighton were postponed because of Covid cases at United.
They returned to action at St James' Park on Monday, with Rangnick admitting that he didn't like the performance at all.
"We were almost back to full strength with regard to the size of the squad, but we couldn't do that much in training," he said.
"On the other hand, in those two-three training sessions, the team looked good and therefore in Monday's game it was really a bit of a negative surprise, the way that we played with regard to game speed, game tempo and physicality."
