United head into the international break second in the Premier League table to Manchester City on goal difference.
Before arriving on international duty, Rashford justified his return to Jose Mourinho's starting XI by providing two assists in United's 4-0 over strugglers Crystal Palace on Saturday.
Martial then provided an assist after replacing the England striker, and the duo have been competing for a starting place out-wide in the first few weeks of the campaign, which Rashford believes can benefit both players.
"Without it, you don't improve," the 19-year-old said. "Young players need that sort of environment around them.
"I think we're both enjoying our football at the moment, we're both having our say in the games, and it's good for us, good for the manager, good for the team."
Competition for the role as central striker is incredibly tough for Rashford for both club and country, as in-form duo Romelu Lukaku and Harry Kane are almost guaranteed starters to lead the line for Manchester United and England respectively.
When asked if Rashford would prefer a role as a No 9, he said: "That's not in my hands. If I'm not playing there, I'm not playing there.
"But wherever I'm playing, I try to get the same results. Obviously, you have to do it in a different way but it's not my decision."
The United man sees himself as a striker long term, but understands that he won't always be able to play in his preferred position.
"I'm a striker but if you have to play elsewhere to wait for your time, so be it.
"The coaching [at United] is very good, but they also try to turn you into good people as well as good players," Rashford said.
"I'd probably say it's about having a lot of respect for everyone, regardless of who they are or what they're doing. That's probably like the baseline you have to have no matter what age you are.
"Just having that alone can get you a long way. It's the main message they give you. United are very good at nourishing abilities.
"There's loads of different examples I can give you of ways they keep us grounded."