Southampton manager Ralph Hasenhuttl hailed Stuart Armstrong as "a very smart player" after the Scotland midfielder signed a new three-and-a-half-year deal at St Mary's.
The 28-year-old, who has made 79 Saints appearances since arriving from Celtic in 2018, has committed his future to the club until 2024.
Hasenhuttl said: "I am very happy with this news. Stuart is a very smart player and is someone who is important for our team.
"He has become more comfortable and confident playing in the number 10 position, and it has been pleasing to see the development he has made as a result of the work he has done with us on this.
"I think he is someone who can continue to improve and make a very positive contribution for us here in the future, so it is good for the club and for him also to sign this deal."
Southampton currently sit ninth in the Premier League, with only three points separating them from the top four.
And Armstrong is keen to continue their upward trajectory under Hasenhuttl.
"I'm very happy," he said. "It's a great group, we're doing well, it's very positive, and to extend my time here and be part of the club going into the future is something I'm very happy about.
"It's a great club to be a part of and it's a club that has a feel of positivity and heading in the right direction."
