Matic featured 35 times in the English league last term, according to WhoScored.com, and he is destined to become a regular at Old Trafford.
"I think you saw that past year", he said.
United lost 2-1 to the LaLiga giants but Mourinho remained upbeat after the Skopje encounter, picking out Matic in particular for praise. You've got to understand what the club is all about.
"We can but we can also play with four in the back", he said.
"Matic has intelligence and experience of the Premier League". Was it his dream to go and play for Manchester United?
Chelsea have strengthened too, but not as much as they would have liked given the added demands of Champions League football - but Giggs thinks they will still be in the mix.
Prior to his first "official" goal for United, Lukaku had already scored three times for the club during pre-season with strikes against Real Salt Lake, Manchester City and Valerenga.
Despite that miss potentially denying United a chance at taking the Champions League winners the distance, Mournho was happy with his new number nine.
"He seemed like he wanted to leave previous year at times, although he was very influential and played very well", he said of Costa. "I think we just have to accept it and move on".
"It's a hard job to play against a team who dominate possession", Mourinho said.
"We just develop that and we played in a couple of matches, Sampdoria and I think the LA Galaxy, because it is something during the season we are maybe going to do". "It would be silly to dismiss Chelsea after the way they played so dominantly a year ago but looking at the teams, I think City and United will be up there and the teams to watch".
Almost 12 months on from his then world record transfer from Juventus, Pogba has emerged as a leader within Mourinho's squad and will certainly be looking to push on this season.