Southgate has infused England's squad with a vibrant crop of emerging stars and Kane was relieved to see them cope with the pressure of playing in a major tournament for the first time.
While the experienced Raheem Sterling grabbed England's second-half winner at Wembley on Sunday, Kalvin Phillips, Declan Rice, Phil Foden, Mason Mount and Tyrone Mings played their part in the vital victory.
Those five are all new to the unique demands of playing for England during a tournament, with the additional burden of having to live up the expectations of the home fans at Wembley.
England captain Kane was especially impressed with Leeds midfielder Phillips, who provided the assist for Sterling's strike as the Three Lions won their opening game at a European Championship for the first time.