The Red Devils were knocked out of the competition 2-1 by Sevilla at Old Trafford on Tuesday after a goalless draw in the first leg. A brace from Wissam Ben Yedder gave the visitors a 2-0 lead before a consolation strike from Romelu Lukaku.
Matic was bitterly disappointed with United's performance and admitted that they only have themselves to blame for not stepping up to the challenge.
"Of course, we are not happy because we are out of the Champions League," Matic said.
"But this is football, we have to accept it and to focus on the next game, which is very important also for us, in the FA Cup.
''We focus also for the league, but we have to say congratulations to the team, Sevilla. They played really well, and they deserved to go through."
When asked if the intensity of the Liverpool game affected United, Matic added: "There is no excuse. There is no excuse. We had a big game, as you know, against Liverpool. We won.
"With high confidence we come to play this game, but today they played better than us and they deserved [to win].
"We have to forget this. We have to see made mistakes, to see what we have to do better and on Saturday is a new game.
"Life goes on and this is football, we have to accept that."