Connacht have won all four games to date in this season's comeptition but Montpellier's only defeat has been against the westerners, so everything is to play for at the Sportsground on Friday.
Brett Wilkinson has been passed fit to play in the front row, having recovered from a hand injury, with Troy Nathan moving to full-back in the absence of the injured Gavin Duffy (cracked cheekbone).
Speaking ahead of the crunch clash, Connacht coach Michael Bradley said: "It is a huge game for us. We always felt this match would be pivotal.
"If we beat Montpellier, we effectively win the pool as we should beat Madrid in the final pool game, so with six wins you would hope to secure a home quarter-final.
"That would be a good progression for this side, and that would be a great target for us and Connacht Rugby come April.
"In cup matches in the past and in one-off matches you have seen that Connacht can win those games, so if you get to a quarter-final, then you can get to a final.
"Montpellier will travel with confidence. They know that when we played them in Montpellier it was a very close game and they probably could have got a draw in the last few minutes had they taken their kicks at goal.
"Instead they tried to run in a try to win the game - that's how close it was."
"Every player would be fighting for places to get on the pitch, and it presents a huge opportunity for us.
"We had hoped we could push on after the two wins over Worcester, but the weather stalled that, so a good performance on Friday would help to kickstart us again for the rest of the season and the Magners League.
"Sometimes when you are playing week after week it can be mentally draining, but this week it's different. We have trained hard and everyone knows it's a big game and is raring to go."
CONNACHT (v Montpellier): Troy Nathan; Liam Bibo, Niva Ta'auso, Keith Matthews, Fionn Carr; Ian Keatley, Frank Murphy; Brett Wilkinson, Sean Cronin, Robbie Morris, Michael Swift, Bernie Upton, Mike McCarthy, Ray Ofisa, John Muldoon (capt).
Replacements: Adrian Flavin, Ronan Loughney, Jamie Hagan, Andrew Browne, George Naoupu, Conor O'Loughlin, Miah Nikora, Aidan Wynne.