Strong central defender joined us from Newcastle United in August, 2009.
And he could not have made a better start to his Spurs career - scoring the winning goal against Liverpool on his debut in our opening game of the 2009-10 season.
A Cameroon international, Sebastien was a regular fixture and reliable figure at the heart of our defence his maiden campaign.
With fellow centre-halves Ledley King and Jonathan Woodgate injured for the majority of the season, Sebastien's regular partnership with Michael Dawson at the back was a solid foundation on which the team was built.
He eventually made 38 appearances for us in 2009-10 including 25 starts out of 38 in the Premier League as we achieved a top four finish. His form earned a call into Cameroon's World Cup squad.
At the start of the following campaign, Seb earned the distinction of becoming the first Spurs player to ever score a Champions League goal - and a vital one at that as his header got us back into our Play-Off with Young Boys at 3-0 down in the first leg, a tie we would go on to win to qualify for the group stages of the competition for the first time in the Club's history.
But Seb's chances were restricted due to the form of William Gallas, Michael Dawson and Younes Kaboul and he went on to make 19 appearances in 2010-11.
Sebastien moved to England, and previous club Newcastle, in July 2008 from Metz where he made 79 appearances in three seasons.
He played 34 times for the Magpies during his debut campaign in the Premier League, but could not help the North East side avoid relegation from the Championship, before arriving in N17.