The young England attacking midfielder has managed only three Premier League goals this season and has not hit the target in any competition since his double against in Tottenham's 3-1 victory over Real Madrid in the Champions League on Nov. 1.
He also came in for criticism last weekend for an ugly tackle on Manchester City's Kevin De Bruyne during Tottenham's 4-1 defeat at the Premier League leaders.
Pochettino says the 21-year-old, who enjoyed a stunning second half of last season and ended up with 18 league goals, is a victim of his own high standards.
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"His success in two and a half years is massive, a fantastic achievement," Pochettino told reporters ahead of Saturday's away clash to high-flying Burnley.
"It's not that he isn't doing good -- the problem is that in the past he was amazing.
"Sometimes to be consistent, a player needs to go down to come back up. The most important thing now is support from the club and the coaching staff, to trust and help him reach the same levels as before."
Pochettino said his tackle on De Bruyne, which could have resulted in a red card, was perhaps out of frustration.
"I don't think he had a bad intention to hurt someone," he said. "I think it was because the result wasn't good for us and sometimes you want to do more, you want to run, you want to tackle and recover the ball and sometimes you arrive with bad timing. We need to help him more."
Tottenham, title challengers for the past two seasons, are down in seventh place, one below Burnley, and are in need of a run of wins to revive their hopes of finishing in the top four.
"There are different circumstances. Some teams have improved a lot from last season, like Manchester City. We need to keep going," Pochettino said. "Belief is important. We need to try and change the dynamic, to win games and get close to the top four. It's a long way until the end of the season."
Burnley earned a 1-1 draw at Wembley early on in the campaign and continued to impress under Sean Dyche, conceding only three goals so far this season at Turf Moor.
"Our idea is to try and win on Saturday. It will be very tough -- they believe in the way they play.
"At home, they are very tough but the three points are massive for us. We are ready to fight."
(Reporting by Martyn Herman, editing by Pritha Sarkar)
