Mark Sampson's team now need just one point to secure their place in the knockout stages of Euro 2017 after a game of contrasting styles with the Spanish side enjoying more than three-quarters of the ball but unable to create much in the way of clear-cut chances.
The England manager told Channel 4:
"We had to find a way to win, and that's exactly what we did. We knew we needed a win to top the group, and that's a big one for us.
"I can't remember Karen Bardsley having to make a save. We'd have liked to have had more of the ball. But in the second half we got up to the ball quicker and got a bit more territory.
"We've got lessons to learn and we'll be better for Portugal."