Phil Davies' men missed 20 tackles in the European encounter and defensive errors led to all of Montpellier's tries.
Warburton, who made a decent account of himself on his return from a chest infection, admits the Blues' defensive problems are a concern but he reckons the young side will benefit from their French education.
"We could have had an a lot better defensive line to stop them going forward," said the Wales captain.
"Montpellier had a very big pack, who offloaded very well.
"They won the collisions and that gave them a lot of momentum. They got on the front foot and did very well to cross the gain line."
Former talisman Xavier Rush was appointed regional defence coach at the beginning of the season and the Blues brought in Rob Powell as a consultant to tackle their rearguard woes.
But they went into the clash with the worst defensive record in Europe and three of their players, Josh Navidi, Lou Reed and Marc Breeze, topped the missed tackle list.
And although Warburton was disappointed with the result he reckons the Blues' young side will benefit from the experience in the long run.
"It was always going to be a tough fixture but it was good for the young boys to come to France," added the flanker.
"It was some of the guys' first taste of Heineken Cup rugby. It is a different intensity from the league and it's a good experience for them.
"Hopefully it will make them better players in the future."