The Ligue 1 champions went ahead through an audacious penalty from Younes Belhanda after just eight minutes, before two goals in as many minutes saw the game switch in the Gunners' favour as first Lukas Podolski and then Gervinho showed good composure to give their side the lead at the break.
Abou Diaby, Vito Mannone and former La Paillade striker Olivier Giroud returned to the Arsenal starting line-up in three changes from the team who comfortably beat Southampton 6-1 at the weekend, as Montpellier made six alterations from the side who lost 3-1 to newly promoted Stade de Reims.
In an intimidating start in the Stade de la Mosson - where the remnants of a multitude of pre-match flares floated menacingly over the pitch - the Champions League debutants were handed a foothold in the game when Thomas Vermaelen's clumsy challenge upended Belhanda inside the area. The Moroccan international picked himself up and dinked a cheeky penalty past the helpless Mannone for his club's first goal in the competition.
|18/1||Arsenal are 18/1 with Bet365 to win the Champions League in 2012-13
The lead did not last long - just seven minutes, in fact - as slack defending allowed Santi Cazorla and Giroud to combine and play in Podolski for a neat finish from 16 yards.
And Arsenal took the lead just two minutes later when another fantastically well-worked goal, started and finished by Gervinho as the Ivorian set Carl Jenkinson free down the left before ghosting past more half-hearted defending from the hosts to collect the left-back’s low cross and tuck the ball past Geoffrey Jourdren.
Responding impressively after going behind, Arsenal looked dangerous on every building attack whereas, at the other end of the pitch, their French opponents where having to make do with pot-shots from distance, their best effort of the half falling to Marco Estrada's low drilled effort from 25 yards out that Mannone did well to see around his near post.
Aside from the clever through-ball for Podolski's equaliser, Giroud was not having the most successful of returns to his old club – much industry but little end product, which was summed up by a twisting run into the area before flashing the shot from 12 yards past the near post in the final action of the first half.
Montpellier came out stronger after the break and were almost gifted another goal when Diaby tried to trick his way out of trouble in his own penalty area and allow Remy Cabella to pinch the ball off him but fire high and wide.
The hosts upped the ante further and again went close when Cabella spotted Mannone off his line and attempted a glorious chip from over 25 yards that thwacked off the deputising goalkeeper's bar and into touch.
In an attempt to make up for his earlier mishap, Diaby embarked on a surging run just after the hour mark that took him past three Montpellier players before feeding Cazorla for a stinging drive that Jourdren could only push away.
As the game entered the final stages, the French outfit showed the much-needed urgency they lacked throughout the majority of the game and it was that man Belhanda who was the fulcrum.
And that was no more evident than when the attacking midfielder switched the play out to the right before receiving the ball inside the area and skipping past the feet of Per Mertesacker, but he soon had his head in his hands after hitting his shot straight at Mannone from eight yards in his side’s best chance of the half as his side's chances of victory evaporated along with the smoke from those simmering flares.