Spain's defeat at home was their first competitive defeat for fifteen years (since June 2003, when Greece beat them 1-0 in a Euro 2004 qualifier in Zaragoza).
A brilliant first-half display was too much for Spain, as England shocked many with their free-flowing counter-attacking football which was brilliant on the eye.
The defence's confidence playing out from the back and the composure displayed whilst playing through the blocks pleased Southgate, as he hailed his side's "courage".
He told 'BBC Radio 5 live': "The quality of the performance - we played with courage and used the ball with courage. If you come and defend for 90 minutes they will unlock you.
"We really showed some quality and a good mentality to play out of their pressing. Spain are very aggressive in the way they press. All our players, right through the team, were brave enough to play the way we wanted to play.
"It's fine to have an idea of how you want to play but to do it is a huge credit to them."