The 21-year-old replaced injured Rio Ferdinand for the clash with rivals City on Saturday and the youngster was one of United’s most composed performers in the game.
“There was an emphasis on me coming into the team because Rio has been so solid, so to play my part in such a massive game and a big title match was brilliant,” Smalling told the Manchester Evening News.
“The players around me make it so much easier. They are always talking to me. When I had my first touch I just felt like one of the other lads who play regularly every week.
“I was talking to Rio on Friday and he was giving me little pointers. He has played with and against Carlos Tevez for many years and seen him in training every day for a couple of years so he was giving me little bits of advice on how to play him.
“He was making the point that Carlos likes to feel the defenders at his back. So you let him have his touch before you move in and go for him. It was great advice because he is a tricky player. It was a really good challenge for me.
“To have that knowledge to tap into is incredible. You get so much feedback with players you are playing with, players who are injured like Rio and the many coaches we have. It really puts me at ease and allows you to enjoy the occasion.
“It is great to have that pre-match advice but you also cannot beat first-hand experience. You can watch as many videos as you want but until you face them it is different.
“I faced Carlos for Fulham last season and I did really well in one match and then another time he got the better of me. So to be able to re-test myself against a world class striker was good
“We played City in the Carling Cup and I did well against him but then we played at Craven Cottage in the league and I was turned too easily and he scored.
“Rio and the coaches were telling me not to do anything rash. Their comments, coupled with what I knew from last season’s experience, helped me. It paid off and I hope it showed.
“I was able to be calm before this massive occasion because I had also learnt from last season at Fulham.
“I have learnt a lot to calm down. At Fulham I think I hyped myself up too much at times and got a bit tense and then I made mistakes. Playing centre-back is all about being calm and that is sinking in now. Now I feel I can relax and play my normal game.
“I am on a high now. I want to finish the season strongly. I hope I can prove to the manager that I can play a part. I am feeling really confident at the moment.”