Unknown to Pochettino at the time, United approached Dier in the summer of 2016 and began “putting pressure on him” in a bid to pique his interest.
In a moment that alarmed the Tottenham boss, Dier and Mourinho were later spotted “laughing [together], speaking in Portuguese” after United’s 1-0 win over Spurs at Old Trafford in December of last year.
Writing in the Daily Mail, Pochettino has accused Mourinho of putting Dier in a “compromising position”.
“I found out that United have made an approach and the player is being destabilised,” he said. “His people have been putting pressure on him, although United are not promising anything.
“Mourinho and I had finished our interviews at Old Trafford [after the 1-0 defeat by Manchester United, December 2016] and the players were doing their warm-down on the pitch. When Jose was done with the press, he stood by the entrance to the tunnel and regarded the returning players.
“He greeted Moussa Sissoko and hugged Dier. They passed by me en route to the dressing rooms, laughing, speaking in Portuguese. Maybe it is a common Mourinho tactic, but he put Eric in a compromising position. You cannot do that after a defeat.”
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Pochettino went on to confront the 23-year-old about the conversation, and believes that the issue is now behind Dier, with the midfielder currently in the second year of a five-year deal.
“‘Are you friends with Mourinho?' I asked him. 'No, but I've known him a long time, from my time in Portugal... one of his godsons coached me. He always says hello.'
“I sat down with Eric after lunch on Monday and we chatted for four hours about the whole shebang: his agent, family, confusion.
“As for the Mourinho incident, 'What could I have done?' Eric asked me.”
“He told me about United's interest since last summer [2016] and I explained the situation to him clearly.
“'Look, you aren't leaving because you signed a five-year deal with us in August. You're among the highest-paid players at Tottenham at the age of 22. You're important to us and you could become the best centre back in the Premier League.'
“Ever since that conversation, Eric admits that he could have waited for Mourinho to be out of sight before heading to the dressing room.”
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