Rashford, who made his first start of the World Cup on Thursday night, told reporters after the game that England must remain positive going into Tuesday's tie.
"The main thing is sometimes it's difficult to keep the positivity and the spirits up, especially after a defeat," the 20-year-old said.
"But we played against a good team with a strong identity and way of playing. It was a good test for us.
"We've not played against that system much since we've been in our system, so it's a good test for us but we have to move on."
England have not won a knockout game at a World Cup since 2006.