Goals from Dominic Solanke and Patrick Roberts fired the Young Lions to a 2-0 victory on Sunday to set-up a clash with Holland to determine the winners of the 2014 UEFA European U17 Championship.
But Peacock’s side were somewhat fortunate to go in at the break level after the Portuguese were denied three times by the woodwork, only for a rousing display after the restart to see England claim their place in Wednesday’s showpiece.
Portugal 0-2 England
UEFA U17 European Championship
Sunday 18 May
Ta'Qali National Stadium, Malta
Following the victory at the National Stadium in Ta’Qali, Peacock told TheFA.com that he thought the second-half performance was excellent.
"I thought we started the first ten minutes quite brightly and then we imploded a little bit," he said.
"A lot of our individual errors were not passing the ball quickly enough. I have to give credit to the Portuguese as they're a very, very good side and make it difficult to get through them. We were very fortunate to go into half-time at 0-0."
"We had to have a few words and try and regroup to get them back to where I know they can be. I thought we were excellent in the second half; they raised the tempo, they were making better decisions, moving the ball quicker.
"There were one or two going through a difficult time out there in the first half and, I have to say, from a character point of view, they dug deep. They regrouped collectively and I think that's great character.
"If you're going to win anything, you've got to have characters in your side who can come back from a bit of adversity."
And Peacock, who guided his country to victory in 2010, is in no doubt which England team will need to show up against the Dutch if they are to win the tournament.
"They have got another gear," he said.
"If they play like they did in the first half, they won't win a final on Wednesday. I'm not expecting them to play that first 40 minutes as they did; I'm expecting them to go out and play the second 40 minutes, which I thought was top class."