The Argentine has been questioned in the past over whether Spurs' high-pressing style results in his players running out of steam, but he said the way that he was rotating his squad meant tiredness was not to blame for recent results.
"Christian Eriksen, maybe can be a little bit tired," Pochettino told a news conference on Thursday. "But mentally more than physically because in the last international duty he played two amazing games."
Eriksen was key to Denmark reaching next year's World Cup in Russia, scoring a hat-trick in a 5-1 playoff demolition of Ireland earlier this month to seal qualification. Pochettino, however, insisted that the playmaker was in top physical condition, like the rest of his players.
"He cannot rest, cannot stop and of course maybe he struggled a bit but his condition is fantastic, after every game the stats are unbelievable," the manager added.
"The other players I think, no, because Dele Alli was not involved in the first three Champions League games, we manage the rotation. This is not the reason the team has struggled."
Alli is another player who has gone off the boil a bit for Spurs of late, but Pochettino said it was normal for a player who is just 21-years-old to have ups and downs during the season.
"He's so young, he needs to find his balance but I am happy with him," Pochettino said. "It's normal we expect so much from him because he's talented.
"We expect him to do unbelievable things every game. Senior players struggle during 10 months to keep the performances, with Dele he is young."
Tottenham head to eighth-placed Watford having dropped to seventh in the table following their midweek defeat at Leicester City.
Midfielder Harry Winks returns to the squad having recovered from a bout of illness, while defender Toby Alderweireld and midfielder (hamstring) and midfielder Victor Wanyama (knee) are still out.
(Reporting by Simon Jennings in Bengaluru; Editing by Christian Radnedge)
