Republic of Ireland youth international Will Smallbone has signed a new four-year deal with Southampton.
The 20-year-old scored on his debut in the Saints' 2-0 FA Cup win over Huddersfield in January.
He has since gone on to become a regular in Hasenhüttl's matchday squad, starting twice in the Premier League, with his first appearance in the top-flight also ending in a 2-0 home victory, against Aston Villa, in February.
The midfielder's form has impressed coach Ralph Hasenhüttl, who said: "Will is a young man who is part of the future of this football club.
"He has made some big steps this season, and he is someone who has a lot of potential to continue to grow as a player. This is the right place for him to continue to do this.
"He has shown in our training sessions and under pressure in matches that he can play, and he is also someone who understands our philosophy as a team and a club.
"He knows where and how he needs to improve his game, and I think that, together, we can develop him a lot in these next few years."
Smallbone, who has been with the club since the age of eight and played for Ireland's U18 and U19 sides, said: "I'm very happy. I’ve been at the club for a long time now, so to commit my long-term future, for another four years, is very special for me.
"To see the manager sign a new contract was big for me too.
"He’s given me a chance this season to, firstly, be in and around training with the squad and then actually give me my chance in the games to play and show what I could do, so that’s a big factor in me committing as well."