Sunderland duo Jordan Pickford and Duncan Watmore helped their country to Toulon Tournament success at the weekend.
And now they have been challenged to prove themselves all over again next season.
England won the Toulon Tournament for the first time since 1994 by following up four group victories with a 2-1 win against hosts France in the final.
Southgate is confident the experience will hold the group in good stead and boost the country's youth development.
And he has challenged the England Under-21 stars to prove themselves all over again next season.
Southgate was impressed by how his team maintained emotional control in feisty matches against Portugal and Paraguay, which he hopes sees them return home better players.
"It's in their own hands," Southgate told the Press Association when asked about the squad's potential.
"They'll take great comfort for having come through a final.
"I think it will inspire them and inspire others to want to be a part of it.
"But with their clubs and with us they've got to prove themselves all over again next season.
"I like the way we played.
"We had a bit more physicality about us. We were able to press the ball more and defensively that gave us more solidity.
"We've moved the ball well over the past three years but we had a real goal threat and were ruthless.
"The goals to chances ratio was really high.
"A lot of good things have happened with this squad, and who knows where they'll be in 12 months' time."
Meanwhile, Sunderland boss Sam Allardyce is keen to be reunited with £10million-rated West Ham United striker Diafra Sakho, according to reports.
The Echo reported over the weekend that Sunderland were weighing up a move for the frontman.
And the Daily Mail are now reporting that the Black Cats are ready to press ahead with a move for the Senegal international.
The 26-year-old is said to be keen on a new challenge, with West Ham co-chairman David Sullivan ready to give him the go-ahead for a summer transfer.
And finally, Allardyce has been hailed Sunderland’s saviour with eight out of 10 supporters crediting him with the club’s Premier League survival.
The vastly experienced 61-year-old arrived on Wearside last October, replacing Dick Advocaat in the hotseat after the club had failed to win any of their opening eight league games.
Sunderland were deep in relegation trouble but he steered the club to safety with a game to spare, ensuring the Stadium of Light will host top flight football for a tenth-straight season.