Napoli won 1-0 on Sunday night through Romelu Lukaku's strike.
McTominay later said: "It's a very important result. We returned to the locker room knowing that it was a difficult match against a good team, who defended well. For this reason it's an important victory.
"I'm happy with my personal performance, I think that in a match you always have to give your best and do what the coach asks of you. You have to listen and learn and as far as I'm concerned I just want to continue doing my best and helping my teammates.
"Serie A is a very difficult championship, there are several teams at the top of the table. It's not easy, it's a tough championship: I don't think people realise how tough a competition it is. We have to be focused in every game. The people in Naples are incredible, I love them. They give you so much passion and warmth and that makes a big difference."
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