The Three Lions set up a Wembley semi-final against Denmark with a convincing 4-0 victory over Ukraine in Rome on Saturday night.
The result extends a fine run for England at the finals and continues a streak of clean sheets since the tournament began.
While there was plenty of praise for the likes of Harry Kane, Luke Shaw and Raheem Sterling, Southgate was quick to hail his entire 26-man squad, including Sheffield United goalkeeper Aaron Ramsdale
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“They gave a fantastic performance,” he said of his team.
“Not only the players that started but the players that came into the game, they kept the momentum going. We were able to get the players off on a yellow card and a couple that were carrying knocks.
“But actually I’m more thinking about the players I had to leave out of the 23 and the ones I didn’t get on the pitch. They’ve been such a massive part of what we’re doing and it’s so difficult to keep a squad of this size involved, happy, feeling valued.
“Those guys have been phenomenal with the way they’ve sacrificed themselves for the group and understood the importance of the group.
“We’re in a semi-final because of that spirit, in a lot of aspects.
“Of course the quality of the play is important. But I’ve seen lots of nations go out of tournaments because the spirit hasn’t been like these guys have got.
“It’s something very special that they’ve got to recognise.”