Connacht's lack of squad depth could prove to be costly in their Champions Cup campaign, according to RTÉ Rugby analyst Donal Lenihan.

The westerners are preparing for a first tilt at Europe's premier club competition in three seasons by virtue of their top-three finish in Conference A of the Pro14.

Their final game before the tournament was far from ideal though as they were soundly beaten by Leinster in Galway last Friday night.

Connacht will be hopeful that Dillane will be available on Sunday

It was a weakened Connacht side, with Quinn Roux, Gavin Thornbury and Ultan Dillane all unable to take the field due to injury. Finlay Bealham lasted just three minutes in the match, while Sean O'Brien also had to come off before the end after damaging his shoulder.

And Lenihan told RTÉ 2fm's Game On that it leaves them short heading into Sunday's clash with Montpellier at The Sportsground.

"They were in trouble from the start (against Leinster)," he said.

"It doesn't help when you're down so many guys in the front row. When your set-piece is under pressure like that, it does impact on performance.

"They fought so hard last year to get into the Champions Cup, but you have to have strength in depth when you're competing on two fronts."

"Montpellier, as with all Top 14 sides, will have a bruising pack. Unless Connacht get a few players back, they already appear to be on the back foot."

Home games are critical in Europe, and Connacht will need to make their games in Galway count if they're to emerge from a pool which also contains Gloucester and Toulouse.

According to Lenihan, Connacht have a coach who can turn things around quickly.

"They've a very smart coach in Andy Friend," he says.

"He's a very experienced coach; he's been around the block in England and Australia. He'll know that you get days like that, and that you just have to reset the bar and go again.

"Leinster, on their day, can do what they did last Friday night, so I don't think Connacht need to dwell on it too much."