It certainly was a game of two halves, Stade Rochelais enjoying the greater return and going in at half-time leading 19-7.
The second half saw a much-improved Munster performance and if stand-in captain James Coughlan caught the eye in the opening half, it was Peter O'Mahony who took on the mantle after the break.
Munster started brightly enough but the first time the home side got into the Munster 22 they emerged with a try. Full-back Benjamin Dambielle managed to score wide out on the left.
Declan Cusack had an opportunity to reduce the deficit two minutes later but his effort, from a difficult angle 30 metres out, missed the target.
Neat footwork from Stade Rochelais out-half Sebastien Fauque led to a try for centre Vincent Roux which Dambielle converted.
The hosts might have gone further ahead if the excellent Coughlan had not managed to block down Fauque's drop goal attempt.
Munster suffered further misfortune in the 28th minute. As they pressed deep inside the La Rochelle 22, Maxime Lebourhis picked off a poor pass and raced the length of the pitch for a seven-pointer and a 19-point lead.
As had always been the intention, McGahan sent on a number of replacements at half-time. The entire pack was changed with the exception of Billy Holland.
It was three of those half-time replacements, Sean Scanlon, Niall Ronan and debutant Ian Keatley, who manufactured Munster's second try.
Munster countered from inside their 22, Scanlon kicked downfield, Ronan made a marvellous steal and Keatley finished it off with the try and then added the extras.
The home side looked a little out on their feet in the final quarter as Munster pushed for the winning score, but it was the unforced errors that cost them in the end. However, overall both the players and management will be pleased with the exercise.
STADE ROCHELAIS: Benjamin Dambielle; Maxime Lebourhis, Vincent Roux, Jerome Jacquet, Florian Ninard; Sebastien Fauque, Damien Neveu; Petrisor Toderasc, Franco Pani, Gaetan Guyon, Franck Jacob, Romain Sazy, Romain Carmignani, Peio Som, Thomas Soucaze.
Replacements: Benjamin Geledan, Stephane Clement, Cobus Grobler, Alfie To'oala, Benjamin Ferrou, Guillaume Devade, Damien Cler, Tamato Leupolu, Antonio Uini, Ignacio Rodriguez Muedra, Robert Mohr, Nicolas Djebaili, Quentin D'Aram De Valada, Steeve Barry, Arthur Cestaro.
MUNSTER: Johne Murphy; Denis Hurley, Danny Barnes, Scott Deasy, Simon Zebo; Declan Cusack, Gerry Hurley; Wian du Preez, Damien Varley, Stephen Archer, Billy Holland, Mick O'Driscoll, David O'Callaghan, Tommy O'Donnell, James Coughlan (capt)..
Replacements used: Sean Scanlon for Barnes, Ian Keatley for Cusack, Peter Stringer for G Hurley, Marcus Horan for du Preez, Denis Fogarty for Varley, Peter Borlase for Archer, Ian Nagle for O'Driscoll, Peter O'Mahony for O'Callaghan, Niall Ronan for O'Donnell, Paddy Butler for Coughlan (all half-time), JJ Hanrahan for Deasy (52 mins), Mick O'Driscoll for Holland (65).