Rashford’s only start for England came in a goalscoring debut against Australia last May and his inclusion in the senior squad means he will miss this summer’s Under-21 European Championship.
The Football Association previously indicated young players needed tournament experience but Rashford, who has won eight caps, says he is “happy” to be in Southgate’s squad.
“We both look at it on the same side of things, so it’s important to be on the same page,” he said.
“Whatever age group you’re called up to, it’s important to have the mindset that you’re going to achieve great things.”
Rashford played 58 games for United and England this season, scoring 11 goals, having broken into his club’s first-team last term and been part of the Three Lions’ Euro 2016 squad.
“To me, I have not been fast-tracked, there’s been a lot of games,” added Rashford. “I feel comfortable in the position I’m in.
“England and United have both dealt with it in a positive way and they are dealing with the situation well.
“A lot of it is mentally. If you prepare yourself mentally the right way then physically you’ll be able to push yourself through it.”
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