And Mjallby insisted that England's penalty - awarded for a challenge on Michael Owen - was dubious.
Prior to England's 1-0 win in Sapporo, Sweden had defeated Nigeria 2-1 to seize the initiative in the group.
"
I think England's was a doubtful penalty, but that's how it is in football
"
Johan Mjallby
But Sweden now face Argentina in their final group game knowing the South American team need to win to guarantee their passage to the second round.
"It isn't an ideal result and naturally the goal was a disappointment," said Mjallby.
"I think it was a doubtful penalty, but that's how it is in football.
"I think it's important for us that we don't have too much respect for Argentina. We're leading the group and now it's up to us.
"We'll go out and try to play our game and hopefully get a goal.
"But we've also shown that we can turn a match around twice in a row, although Argentina will do all they can to shut us out."
Joint-coach Tommy Soderberg is confident his side can get a positive result against Argentina.
"Everyone knew it would be a tough group," he said.
"But no-one would have believed it if someone had said before the World Cup that we would be leading after two matches.
"We've gone a goal down in those two games and managed to turn it around, and that's an incredible strength."