England reached the European U21 Championship semi-finals with a thoroughly deserved 2-0 victory over Spain.
Milner had earlier seen his penalty saved by Spain keeper Sergio Asenjo but in the end this was the only disappointment of a successful night for the young Three Lions.
Spain rarely threatened in a lacklustre performance that now sees England face Germany on Monday in their last group game, with the semi-finals to be played on Friday 26 June.
"I'm pleased we're through, but I'm not surprised because I know the character of these boys and it was a gutsy performance," said a delighted England coach Stuart Pearce.
"It was a great reaction from Theo (Walcott) - but for me it wasn't even a big decision. Getting over the finishing line is what's important and he helped us to do that with a virtuoso performance from the bench.
"Even though it's his birthday today, Fabio Capello phoned me straight after and wanted me to pass on his congratulations to the players."