Norwich's England Under-21 international Nathan Redmond scored the game's only goal to condemn Southampton to their first defeat of the season.
But Pochettino felt that his side should have had a first-half penalty when Adam Lallana's shot cannoned off Bradley Johnson's outstretched arm, with referee Howard Webb motionless.
"It was a defender in the box (who handballed) and it should have been a penalty," said Pochettino.
"The overall feeling is that we played well, that we deserved a bit more from that match.
"We don't want to take credit away from Norwich, they actually played very well, but there was a penalty call that was not given and that would have changed completely the nature of the game.
"The referee was very close to the action so I really have no idea why that penalty wasn't given, it was blatant. It could've changed the game completely."
He added: "In the first 15 minutes Norwich were dominating the game, but after that I think we were able to match them and their strength and their effort. I think after those 15 minutes we played well.
"In the second half when we were playing our best football we conceded a goal and it was very hard to come back from that."
"I think it's normal that (Osvaldo and Rickie Lambert) weren't able to link up well, it takes times for a player to gel and to get into a squad.
"It's their first game together and he needs time (before he can) play well with Rickie."
