Ole Gunnar Solskjaer’s side looked set to escape from the King Power Stadium with a fortuitous point after the forward came off the bench to score on his first appearance since summer shoulder surgery.
But Jamie Vardy and Patson Daka goals in quick succession sealed the Foxes a 4-2 victory that heaped pressure on United at a key period of the campaign.
“I think at a club like Manchester United, as soon as you lose a game this is what happens,” Rashford said. “I think for us as players, we have to go back to basics, look at ourselves and see what we can do better.
“We’ve had the conversation as a team as we would do whether we win a game or lose a game. We know the next game is another opportunity to improve and that’s always the aim.”
United take on Atalanta in the Champions League on Wednesday looking to get back to winning ways ahead of Sunday’s Premier League clash with big rivals Liverpool.
“It’s not only after defeats. After some games when we win when we know we’ve not played well, it’s as important, if not more important, to have those conversations because you want to nip it in the bud as soon as possible,” Rashford said of the players’ post-match debrief.
“Especially in the Premier League you have to defend well and I don’t talk about just the back four. As a team you have to defend as one and against Leicester we were just too open. It’s as simple as that.
“They’re a good footballing team as there are a lot of them out there and it was too easy for them to play through us and we’re going to do our best not to let that happen again.
“The game (on Wednesday) is the first opportunity to show that’s what we’re focused on.”