Since then, Montpellier have been beaten by Ulster and Leicester Tigers home and away, with the top two booking their own places in the last eight with a week to spare as a result.
But despite the disappointment of those defeats, Glas knows things could have been very different given that they scored four tries in the East Midlands and were within a minute of winning the return leg against the Tigers at the Stade Yves-du-Manoir last month.
He sees no need, therefore, to criticise his players for failing to back up last year's quarter-final showing and instead insists they will be all the better for the experience.
"It was complicated for us this year. When I saw our three opponents in the pool, I knew it would be very difficult," said Glas.
"When you play in the Heineken Cup, however competitive a team you have got - and we certainly have one - nothing is certain. There is no room for mistakes.
"It's disillusioning and disappointing for us because we were quarter finalists last year but everything goes so fast in the Heineken Cup: one lost game and you're almost out.
"At the end of the day it is very disappointing but we have to keep in mind that our pool was a really big challenge."
On paper, Treviso at home this weekend should be the easiest assignment to date but Glas says Montpellier have no intention of just limping to the finish line despite the fact that they know they won't be involved in the knockout stages in April.
Montpellier showed impressive spirit against Ulster at Ravenhill last Friday, a spirit that was summed up in a remarkable rear-guard action that prevented the Irish outfit from picking up a fourth try in the final quarter, and Glas expects more of the same in Round 6.
"We will try to keep our positive state of mind and try to use what worked well against Ulster again this weekend," added Glas.
"We fought well over there. We showed lots of commitment and I hope we will be able to keep the same intensity against Treviso before our Top 14 game versus Bordeaux-Bègles.
''We have nothing to reproach our players for - they invested themselves fully and were always aggressive. We can't forget that there was nothing at stake for us. The Irish side had 25 minutes to score the fourth try but we kept defending well. That shows a lot."