Jose Mourinho has suggested on a regular basis over recent weeks that success in Europe is now the top priority for the Red Devils.
He has hinted at shuffling his pack accordingly, allowing him to rest key men domestically in order to keep them fresh for continental challenges.
Herrera, though, says that everyone connected with United has a responsibility to honour the traditions of the club and ensure that full focus is given to each passing fixture.
The Spain international told Sky Sports ahead of a crunch clash with fellow top-four hopefuls Arsenal: "We are ready. We are in a good moment. We are a difficult team to beat. It is not so easy to score against us.
"We know Arsenal are a very good team, they have some special players who can change the game in one moment, but we are really ready, ready to go there and try to win. That's the way we have to face them.
"If we lose against Arsenal, we will have another final against Celta, another final against Tottenham, this season is like this and will be like this until the end.
"The only way is to try and win every game. You cannot select games. Every game is important. We are defending Manchester United, we are defending the greatest club in England, one of the greatest in the world. No excuses. Fight for every game.
"We have a lot of injuries at the moment, but we have players coming back. Sometimes in the difficult moments, you find the spirit and everyone works in the same way and pushes together.
"There are players who are not playing every week, but they can help us. We have a very good squad.
“All our focus is on the Champions League. If we get it, it will be a very good season."
United head to Emirates Stadium on Sunday sat fifth in the table, four points behind arch-rivals Manchester City and the final Champions League spot and five ahead of the Gunners having played a game more.