Carrick has welcomed the increased competition for places and believes it can only be to United's benefit.
"That's what it is all about, you've got to be at your best to play for United," Carrick told Sky Sports News after the 2-2 draw with Urawa Red Diamonds.
"The more world-class players we have in the squad is going to benefit us in the long run.
"It's a long season, we will have a lot of games and there will be times when you are in, and times when you're out.
"When you're in you've got to play well. Everyone is raring to go. It's a big challenge this season for us."
The midfielder is on his first long-haul pre-season trip with United and has noted the popularity of the club in the Far East.
He added: "Sometimes - you don't take it for granted - but you get used to the routine of playing in the Premier League week in, week out.
"You come away like this and you realise how big the club is and how big English football is.
"It makes you really aware of what it's like to be part of it and I want to make the most of it."