It is not so long since Glasgow's players would have celebrated the achievement of running the most successful club in European history as close as this, so the grim faces they wore at the end of this match could be taken, perversely enough, as another sign of the progress they have made over the past three or four seasons.

But that interpretation would be entirely the wrong response. Toulouse are not remotely the force they were, a fact borne out by their lowly seventh place in the French Top 14 league, where they have just 50 percent of their games this season. Over the course of the past two weekends, Toulouse have shown nothing of the swagger and sparkle which were once their trademarks and which led them to being crowned champions of Europe an unmatched four times. To put it bluntly, they were there for the taking.

No, the frustration and disappointment for the Warriors players, coaches and fans at Scotstoun arose from the fact that Gregor Townsend's side played a good few notches below the level they are capable of reaching. In a game the coach himself had billed as one of the most significant in Glasgow rugby history, they delivered a performance that was flat, uninspired, disjointed and riddled with errors. They can take some consolation from the bonus point secured by two late penalties from Duncan Weir, but had they played to their true potential they would already be checking the dates of the Champions Cup quarter-finals.

Instead, as Townsend admitted, progress to the knockout stages will require wins in their final two games next month: at home to Montpellier and then away to Bath. A tall order, but not an impossible one. If Montpellier, winless after four rounds, follow French tradition and pretty much give up the ghost at this point, then Glasgow can target a bonus-point victory against them. And if Toulouse maintain the European form they have shown to date then they can probably be expected to beat Bath that same weekend.

So already it looks likely that the Warriors match at the Recreation Ground on January 24/25/26 - the exact date should be known early this week - will be the most critical of their season. All this involves a few assumptions, of course, and in the swirl of variables and permutations it is still even possible that Bath will go into that game chasing top spot in Pool 4, and the home quarter-final that would bring. But in all of this, the fundamental point for Glasgow is that they cannot afford another slip up.

"We've got Montpellier next and if we don't win that we're out of the competition," said Townsend. "We've played a really good side and finished up eight points behind last week and three points now. We've performed pretty well in this tournament and now we've faced a tough team. We have to take that lesson and make sure in the next two games we come out with wins."

The not-so-thin red line of the Toulouse defence was Glasgow's undoing on Saturday. Glasgow's attack was an unstoppable force in some early games this season, but they came up against some pretty immovable objects in this game. In normal circumstances, churning through the phases and around the fringes will usually create a gap for a strike runner to exploit, but Toulouse were so infuriatingly good in contact - they rarely committed more than a couple of players to a ruck - that those spaces never opened up.

"We didn't seem to get in the flow of our game," said Glasgow flanker Richie Vernon, whohad been the Glasgow No.8 in 2010, the last time Toulouse visited these parts. "They competed really well at the breakdown. And it's frustrating because we had lots of chances down the in the 22.

"I think conditions meant that defences were on top and we weren't able to turn those situations into points. We felt we did enough to win the game but credit to Toulouse."

Nor did it help Glasgow's cause that Finn Russell had such a dismal day at the office with his kicking. The starting fly-half was given four penalty opportunities but landed just two, and neither of the kicks he missed were particularly testing by his standards. There was, moreover, a distinct impression that he hesitated too long in what is usually a refreshingly relaxed his pre-kick routine, which is often a sign that the weevils of self-doubt have taken up residence in a kicker's mind.

On Russell's behalf, Townsend denied that suggestion. "It seemed normal to me," countered the coach. "Last week he was excellent, and against Montpellier [in the previous European game] excellent again.

"It comes to goal-kickers every now and again, and that's why you don't get 100 percent goal-kickers. It's tough for him because this was a really important game. I have empathy because I've missed those kicks for Scotland and at clubs I've played for."

Glasgow suffered a dip around this time last season, when they may even have been lucky that two games were cancelled due to pitch problems. There was a curious mood around Scotstoun for a time and they did well to rid themselves of it in time for their magnificent spring run. As their next three fixtures will involve clashes with Guinness PRO12 leaders Munster and then back-to-back matches against Edinburgh, Townsend must hope that the flatness that was evident on Saturday does not take hold at the club.