"We cannot extend the contract and improve the salary every few months. I don't like to talk about rumours. The most important thing is that he is happy and performing well," Pochettino told reporters on Thursday.
Tottenham went on a seven-game winless run after beating Manchester City in October and Pochettino urged his side to prove they have learnt to build on impressive victories by picking up a win when they host eighth-placed West Bromwich Albion on Saturday.
"Remember a few months ago after City, I think now it's a moment to show we learned," the Argentine said.
"We have in front a very tough game and we need to show that we learned from a few months ago. If you remember we dropped our performance a bit after a fantastic victory.
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"After Chelsea it's a great opportunity to show that we deserve it and to keep our momentum is key."
Tottenham, who will be without injured winger Erik Lamela for Saturday's clash at White Hart Lane, are third in the table with 42 points, six behind leaders Chelsea after 20 games.
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by Jon Boyle)
