The Dutch failed to qualify for the last two major tournaments, but have bounced back by beating world champions France and Germany to make the semi-finals of the inaugural Nations League, where they meet England in Portugal on Thursday.
Koeman saw at close quarters England's struggles during his stint as a Premier League manager at Southampton and Everton. watching the Three Lions crash out at the group stages of the 2014 World Cup before they were embarrassed by Iceland at Euro 2016.
However, since Southgate's appointment, England have reached their first World Cup semi-final for 28 years and edged out Croatia and Spain to make the last four of the Nations League.
"I think at that time it was maybe a difficult period, but when Gareth took it over they gave possibilities, chances to young players," said Koeman at his pre-match press conference in Guimaraes.
"Southgate is doing a fantastic job, it was an example for the Dutch team how they processed the squad and gave chances to young players."
Koeman has quality youngsters of his own to count on. Matthijs de Ligt, Frenkie de Jong and Donny Van de Beek all shone in Ajax's run to the Champions League semi-finals.
De Jong has already agreed a move to Barcelona, while De Ligt could join him at the Camp Nou as he is wanted by a host of top European clubs.
A former Barcelona defender himself, Koeman admitted he has given his advice to the 19-year-old De Ligt over where he should move for the next stage of his career.
"He is a great player already and he will be better in some years. Let's hope he chooses for a big, big club," said Koeman.
"I spoke to Matthijs one week ago about his future and that's secret.
"What I told all the young players, the most important is keep playing. Keep getting minutes to develop your football.
"Also how the club is playing is really important to make your choice."
De Ligt has a role model to follow in Dutch captain Virgil van Dijk, who will lead his nation on Thursday just days after winning the Champions League with Liverpool.
Koeman confirmed Liverpool midfielder Georginio Wijnaldum will also start, but Southgate has a tougher task with seven of his 23-man squad involved at the weekend.
And after losing the Champions League final last season, Van Dijk admitted it is easier to deal with the quick turnaround after a win.
"I remember from last year when I came back, I felt bad, I felt disappointed for quite a while," said the world's most expensive defender.
"It's easier than last year in the spirit of disappointment. Physically and mentally I am in a better place now."
Van Dijk could come up against Harry Kane once more after the Tottenham striker returned from a two-month injury absence to start in Madrid on Saturday.
However the England captain looked well-short of match sharpness and may well be left out by Southgate.
"Harry Kane is a fantastic striker. Definitely the best striker England have," added Van Dijk.
"I know also if you are not 100 percent it is in your head. I expected him to play the final but I know he wasn't 100 percent."