Mauricio Pochettino thanked Southampton for his time at the club after opting to take over as head coach of Tottenham.
It was announced on Tuesday that the Argentinian would take over from Tim Sherwood at White Hart Lane and has signed a five-year deal.
Pochettino was appointed Southampton first team manager following the departure of Nigel Adkins in January last year, and guided the club to 14th in their first season back in the Premier League.
They were then one of the success stories of the 2013-14 campaign, finishing eighth with a group of young English players forming the core of the side.
Following the announcement of his move, Pochettino released a statement via Southampton's official Twitter account to express his gratitude to the club.
"I would like to thank everyone at Southampton for the support that myself and my coaching team have received during our 18 (actually 16) months at the club.
"We have been on an incredible journey and enjoyed some great experiences.
"I will always have fond memories of my time at St Mary's and wish everybody the best for the future. I hope the team can continue to prosper."