The 21-year-old became the club's record signing when he moved from Ajax to Spurs for £35m in August.
Sanchez has made a solid start to life in North London, putting in particularly impressive performances against Real Madrid and Borussia Dortmund in the Champions League.
Speaking of the Colombia international, Pochettino told Sky Sports News: "He's so clever, he's very humble and he's very open to learn.
"He's a player when you tell him something his reaction is to be open and be critical with himself and that is a massive skill from a player.
"When he's so open to improve, then the conditions are amazing to be one of the best centre-halves in the world."
Up next for Spurs is Saturday's Premier League game against West Bromwich Albion at Wembley Stadium.