The host nation disappointed in their opener against Greece but recovered with victories over Russia and crucially old rivals Spain to progress to the quarter-finals.
Luiz Felipe Scolari made big decisions after that Greece defeat and Jamie sees the arrival of midfielder Deco and central defender Ricardo Carvalho as key moves.
Jamie, in Portugal in his role as a TV pundit, said: "I wasn't that impressed with Portugal in the first game, they looked nervous but since then they've come on really well.
"Scolari has brought Deco back into the side, left out Rui Costa and that was a good move and brought in the centre-half Carvalho for Fernando Couto.
"Costa and Couto are good players but the youngsters needed to be given chance and that's why Portugal have done so well in their last couple of games.
"But I think England are looking strong," he added. "I'm not trying to be wise after the event but I've always felt that England had a good chance.
"I thought we would get through the group and we still have the chance of winning the tournamemnt. The Portugal game will be fantastic to watch and I'm really looking forward to that."
Jamie Redknapp believes Portugal have improved as Euro 2004 has progressed - but still fancies England to do the job tonight.