The Saints slipped to their first defeat of the season after Nathan Redmond's fine strike in the 68th minute but Pochettino believes his side should have been given the opportunity to take the lead much earlier, when Bradley Johnson blocked Adam Lallana's shot with his hand in the first half.
The decision by referee Howard Webb left Pochettino dumbfounded.
"The overall feeling is that we played well and deserved a bit more from that match," the Argentinian said.
"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. It was a penalty that should have been given.
"I don't understand why it wasn't given. The referee was very close to the action, so I really have no idea why it wasn't given.
"It was blatant. It could have changed the game completely."
With two weeks until the next match due to the international break, the attention is now focused on the final few days of the transfer window.
Saints are hoping to shift a few players before Monday's deadline and there were reports that Jack Cork was subject of a bid from Fulham.
"I don't know anything about that," Pochettino said.
"There's no offer from Fulham, I don't know anything about what you're saying.
"He's a first-team squad member, he's a part of this team. If we start selling players we're only going to be left with just 11 players, so no."