Alli will miss England’s World Cup qualifier with Slovenia tomorrow night after landing a one-match ban for an offensive gesture during the 2-1 win over Slovakia.
But Southgate claims the punishment was a “fair outcome”, and has spoken to the Spurs forward to make sure it never happens again.
The England boss said: “It's quite a unique circumstance. It's probably a fair outcome. I've discussed it with Dele throughout.
“He recognises his responsibilities and how things will be viewed, and how his world is changing in terms of the attention and spotlight on him.
“He won't do it again, that's for sure. It's an experience he'll have learned from. We've had good conversations about loads of different things.
“Now my focus is him being ready for the game on Sunday, making him aware of how we're playing and everything we're trying to do with the team.
“There's a desire to know everything we discuss, but he's a player we enjoy working with. The things he does on the pitch in terms of creativity and the way he plays are a result of his character.
“With that character you do things immediately and think about them afterwards. These experiences will make him better going forward.”
Southgate also hinted he believes Tottenham star Alli needs to win a few major trophies before he can be regarded as a truly world class player.
The England boss said: “Is he world-class yet? Difficult to know what that benchmark is.
“With a lot of young players who are on the cusp of something very exciting, but until they perform consistently and win trophies and medals at the highest possible level… then we can start to talk about world-class.
“In terms of his form, he's in the right areas at Spurs, arriving in the right areas. He hasn't scored as many goals as he wants.
“But for every young player there's always opportunity to improve, and he wants to do that as much as anyone else.”
