PSG laboured to a 1-1 draw in Pochettino's opening game in charge, with the former Tottenham boss having replaced Thomas Tuchel.
The Ligue 1 champion moved up to second thanks to Lille's defeat to Angers, but is three points behind leader Lyon.
Saint-Etienne capitalised on Idrissa Gueye's mistake to take the lead, but Moise Kean's eighth league goal of the season cancelled out Romain Hamouma's opener.
Denis Bouanga hit the crossbar for Saint-Etienne after the break, while Kean snatched at a good chance and Angel Di Maria forced Jessy Moulin into action with what was PSG's only shot on target in the second half as the spoils were shared on Wednesday.
"I am happy with the efforts of the players," Pochettino told Telefoot. "We've been trying since our first day to set up different concepts.
"I'm happy with their efforts, their attitude. It's only the beginning. They have to adapt to us [the staff] and we have to adapt to them. There is work to be done to get to know each other better.
"We have to improve in several situations, especially with the ball, but it was difficult because the preparation has was very short.
"I am disappointed, because we are PSG and we want to win. But we didn't have a lot of time to prepare for the match.
"We still have a lot of things to improve, to develop. This is not the result that we wanted."