Steven Davis has penned new terms with Southampton until 2018.
The 29-year-old's current deal was due to expire in 2016, but he has been rewarded for his fine form with a further two years.
"I'm delighted to have signed a new contract," Davis said on Saints' official website.
"I've enjoyed my football since I came here and the club is continually progressing. I'm excited to see where we can go together over the next few years.
"It was a difficult summer for everyone involved, but the board stayed strong and the club made some really good signings in the manager and players that were brought in.
"We've had an exciting start and we're determined to go on and keep progressing. Nobody wants to stand still.
"We want to get better - that goes for the team and myself. I'd like to win trophies and continually try to improve our league position, and I feel we can do that at this club."
