The Derby County starlet capped off a man-of-the-match display with the winning goal in Vinkovci on Tuesday night as the Three Lions beat Croatia by 2-1.
And whilst Southgate is often reticent to focus on individual performances from his players, he couldn’t help but purr over Hughes’ contribution to the win.
Hughes starred in both legs of England's play-off with Croatia
"He was fantastic," admitted Southgate.
"I think he was the youngest player in our team and has played with great maturity in both matches, under scrutiny and the spotlight.
"His touch and his awareness was first-class.
"It’s difficult to single people out because there were so many good performances, but I thought he was outstanding."
Croatia 1-2 England: Match highlights
The Under-21s head coach also revealed it took a few stern words to his players at half time to re-focus them ahead of their masterclass after the break,
"There were 15 minutes before half time when we got a bit passive and stopped passing the ball and it was almost as if we thought we’d scored the goal and that was going to be enough," he revealed.
"We never thought that was going to be enough, so we spoke at half time about pressing higher up the pitch, trusting ourselves with the ball and getting the ball in the middle of the park where we were outstanding all night.
"And going for the second goal, because we knew that would kill the game."
Watch Southgate's post-match message to his squad
