Pochettino began his tenure with an all-out attacking trio in Moise Kean, Kylian Mbappe and Angel Di Maria following the shock axing of Thomas Tuchel.
Saint-Etienne almost made an ideal start when a towering header from Harold Moukoudi forced Keylor Navas to pull off a stupendous save following a corner-kick.
The deadlock was eventually broken by the host 19 minutes in through Romain Hamouma, who charged on to a square pass from Denis Bouanga to find the top-corner of the net.
Kean put the champions level in the midway stage after he turned in the area to send a loose ball from Marco Verratti past Etienne goalkeeper Jessy Moulin.
Di Maria was inches away from putting the visitors in front just before halftime from a powerful volley but blazed over as Navas thwarted a volley from Mathieu Debuchy at the other end.
Etienne made a fast start to the second half as a free-kick from Timothee Kolodziejczak flew inches away from the intended target with Navas hanging by a thread.
Moulin made himself big at the other end with a flying save off an instinctive attempt by Mbappe following good work by the all-conquering visitors.
Pochettino turned to the substitutes' bench on 63 minutes in the hope of getting a winner and pulled on Julian Draxler for Idrissa Gueye with Timothee Pembele entering for Colin Dagba.
Etienne threatened to go back ahead minutes later when Bouanga arrowed a cross into the area from Hamouma onto the crossbar.
The Parisans launched a threat of their own in the closing period with a powerful strike from the area by Di Maria, but it was palmed by Moulin as it finished in a stalemate.