"We've always said we can't use excuses, and we can't blame the heat for poor performances," Beckham was quoted as saying by BBC on Thursday.
"Physically we have struggled at tournaments and in the past couple of games in this tournament we have struggled in the heat.
"But it is up to us to overcome that, there are no excuses now. We're confident we can deal with anything thrown our way," he added.
England coach Sven Goran Eriksson and skipper Beckham claimed that the heat played a major part in their lackluster performance during the group stage of the World Cup.
The Real Madrid midfielder also stated England can cope with their opponents' physical approach, after Portuguese duo Deco and Costinha were sent-off in their country's hard-fought 1-0 win over Holland in an ill-tempered clash in the second round.
"We're English and, typically, we love physical games. We relish a high tempo with tackles flying in so, if that's the way the game turns out, we will relish it," he said.
Beckham urged England's players to keep their discipline as the Portugal game maybe a heated one.
"In England against Portugal there are always things that happen in games. It's always going to be fiery and it is up to us as players to keep our discipline," he said.
"Sometimes it is difficult because you get frustrated and things happen, but you have to stay disciplined," he added.