The Spaniard enjoyed a relatively successful debut campaign in England under new manager Louis van Gaal following his transfer from Athletic Bilbao last summer.
Herrera started 28 games in all competitions for the Red Devils last season, and scored six Premier League goals as the Red Devils secured a fourth-place finish in the top flight.
We have the best players in the world, but I think it’s good for me
United have already brought in four new players this summer as Van Gaal looks to transform his side into genuine Premier League title contenders next season.
However, midfielder Herrera insists that he is not fazed by the added competition for places at Old Trafford as he looks to step his game up in the 2015-16 campaign.
Herrera is quoted as saying by the Guardian: “After one season, I know how well I have to play to keep playing for Manchester United.
“I’m happy with my development last season but this is Manchester United – I have to keep improving if I want to play for this club.
“We have the capacity to buy new players, we have the best players in the world, but I think it’s good for me. I’m a young player, I want to keep improving but, of course, it’s always difficult to keep playing here. Now there are even better players than last season but it’s a good challenge for me.
“I love football, I love my job and I love to improve so I don’t see that as a problem. I see it as a new challenge that will make me better.
“I always believed in myself when I was not playing much [last season],” he continued. “I knew in advance I was coming to maybe the biggest club in the world so I knew it wasn’t going to be easy to play – otherwise I would have stayed in Bilbao – but I love the challenge; I love to have the chance to play for Manchester United.
“Now we have a new season with the chance to play in the Champions League so, when I am not playing, I’m calm because I believe in my qualities.
“Every manager, at the beginning of the season, has his own idea of what the team should be but no team ever finishes a season as it started it. Everyone is going to get their chance.
“The most important thing, if we win something, if we win a title, if we’re playing for the Champions League, is that everyone is going to be important because the big teams are formed with 20-22 players, not only 11.
“I think I was important in moments last season but I want to be even more important this season.”
United kick off their Premier League campaign against Tottenham on the opening weekend of the season.
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