Leicester City man Maguire, who impressed both at the back and going forward in the side's tournament opener, told the Evening Standard that the players have confidence after snatching their first victory.
"There are some top, top teams at the World Cup but none that we are going to fear," the 25-year-old said. "We have been watching a lot of the big teams so far, including the Portugal match with Spain. That was excellent and set the standard.
"But we created numerous chances against Tunisia. You see the other big teams and they haven't had anywhere near as many as we made. We have to take a lot of positives from that.
"We have confidence among ourselves anyway. We are not getting carried away, it is just one game. There are two group games left to play, two that we have to go out and win."
England play Panama on Sunday afternoon, before their crunch clash with Belgium next Thursday rounds off Group G.