London: Midfield enforcer Victor Wanyama became the first player from Southampton to join up with former manager Mauricio Pochettino when he signed for Tottenham from their Premier League rivals on Thursday.

The 24-year-old Kenyan international, who Southampton refused to sell to Spurs last year, will cost a reported £9 million (Dh45.7 million), although with add-ons it could rise to £12 million.

Wanyama signed a five-year contract and is Pochettino’s first signing of the close season, as he builds a side not only for the Premier League campaign but also the Champions League after they finished third last term.

Wanyama said in an open letter that he was sad to leave the club that in 2013 gave him the chance to become the first Kenyan to play in the Premier League.

“I write to you with a heavy heart to announce that I will be leaving Southampton Football Club,” he said.

“As you can imagine it is very emotional for me to say goodbye to the club that gave me the chance to be the first Kenyan to play in Premier League.

“Firstly, I would like to thank the most important part of every club, the fans. It took a while for me to win you all over but I can truly say that with your support and affection I have grown as a player and a person.

“I will never forget my time in Southampton Football Club, I will keep the club forever in my heart.”

Wanyama, who made his international debut aged just 15, impressed for the Saints last season as they finished a best-ever sixth in the Premier League.

Wanyama, who scored four goals in 85 league appearances and had a year to run on his contract, is the second big loss to Southampton in the past week after manager Ronald Koeman left to take over at Everton.

Pochettino was the man responsible for bringing Wanyama to Southampton, signing him from Celtic for the 2013/14 campaign, but the Argentine left for Spurs at the end of that season.

Meanwhile though, Spurs have had a bid for the Netherlands international Vincent Janssen turned down, his Dutch club AZ Alkmaar said on Friday.

“The difference between the offer and the price we demand was too big,” AZ’s technical director Max Huiberts told the De Telegraaf newspaper.

The club want €20 million (Dh81 million) for the 22-year-old forward, who finished his first top-flight season as the highest scorer in the Dutch league, but Spurs had only offered €14 million, the newspaper said.

Janssen had visited London with his agent, but had also been to VfL Wolfsburg in the Bundesliga for discussions, Huiberts added.

“But Spurs have made the only official bid. I’ve read a lot of speculation and been telephoned by other clubs but no one else has made any concrete offer.” AZ paid €400,000 to Almere City for Janssen’s services last year. He had played at the second division team after failing to make the grade at Feyenoord.

Janssen scored for the Netherlands in his second international cap against England at Wembley in March and now has three goals in five appearances.