Dier was booked after his slide tackle on Spain and Real Madrid captain Ramos in the 12th minute of England's 3-2 victory in the Nations League on Monday.
The Spurs midfielder's challenge may have been aggressive and unnecessary, but Pochettino liked what he saw.
Asked if he was proud of Dier's desire in the challenge, Pochettino told Sky Sports News: "Yes of course, very proud."
Dier was one of four Tottenham stars in England's starting XI in Seville, joined by Kieran Trippier, Harry Winks and Harry Kane.
Pochettino enjoyed the performance of his players, who return to domestic action with a trip to West Ham in the Premier League on Saturday.
"I think they were brilliant. We were talking about how the attitude was amazing," he said.
"Against Spain if you do not play with more attitude than them, they have unbelievable players and it makes your job difficult.
"I think they were outstanding and it's difficult to say Eric or Harry Winks or Harry Kane or Kieran Trippier [was best], I think all the team was brilliant.
"The motivation to play against Spain will be so useful [for Spurs]. You need to play with this attitude and then your quality and your talent appears.
"Attitude is important in football for the success and I think it is important for these types of players, I think they have a great potential in the future to win [international] titles."