The 19-year-old left-back was omitted from Roy Hodgson’s senior squad in order to help Southgate’s men qualify for the 2015 European Under-21 championship this week.
And Shaw played his part as the Three Lions sealed a 4-2 aggregate victory over Croatia on Tuesday night, booking their place in next year’s tournament in Czech Republic.
And England Under-21 manager Southgate praised Shaw’s attitude over the past week as the defender knuckled down to help his country after his £27m move to United this summer.
“You only have to talk to Luke Shaw to see how much he enjoyed the two matches,” Southgate told talkSPORT.
“He played extremely well and Croatia were a fantastic test for him. He’s shown humility to come down and fit in with the group and that’s what you hope for but it isn’t a given that that happens.
“Raheem Sterling was the same when he came down and played with us earlier in the year and if we can start to breed that mentality in our players then it gives them a great chance of being successful.”
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news