Cardiff gave the knife a cruel twist when Alex Cuthbert grabbed the ball in his own 22 and raced 80 metres for a try six minutes from the end but Glasgow had no real cause for complaint. Their Heineken Cup hopes are now hanging by a thread, and a pretty thin one at that.
Had they taken a bonus point in the Welsh capital last night then things might not have looked so bleak but two defeats and one win in the competition so far has left them in a poor position as far as reaching the last eight is concerned. Even if they can reverse this result at Scotstoun next Friday, they will still be looking at a steep uphill climb.
Glasgow simply lacked the bite in contact to establish a dominant pattern against their understrength opponents. They coughed up the ball far too easily and made errors that would have been hair-raising even in a less critical context. Had Cardiff looked more like their real selves then Glasgow could have lost by a great deal more.
"We made things easy for them," admitted Al Kellock, the Warriors captain, rueful at such a disappointing team performance in his 50th Heineken Cup appearance. "We've not been great at Scotstoun in our last couple of home games so we have something to prove there next week. I've said for years that we need to step up in the Heineken Cup. At times we took that step forward tonight in some of what we did, but we were well off in other things. If we don't fix them quickly it will be the same result next week, so we've got a lot of hard work to do."
The uneasy relationship between the Welsh regions and the Welsh Rugby Union was not exactly eased by last weekend's international against Australia, staged outside the official Test window, which cost the Blues the services of Gethin Jenkins and Sam Warburton for this match.
In their absence, and with Bradley Davies also out at the moment, there was a decidedly makeshift look to the Blues pack, although it did offer novelty value in the mighty shape of Chris Dicomidis, a Cyprus international who only signed for the club a couple of weeks ago.
As expected, Glasgow set about their business at a brisk pace, the best of the early action being a sizzling break by DTH van der Merwe in which the Canadian winger left Blues centre Richard Smith for dead. Soon afterwards, however, it was Van der Merwe's defensive skills that were important to the Warriors as he hauled down Cuthbert in full flight a few yards short of the line.
An infringement in the ensuing ruck gave the Blues their first chance of points, but Leigh Halfpenny struck his penalty effort wide. However, Glasgow failed to clear their lines adequately, were pinged in another ruck a few seconds, and there was no mistake by the Lions full-back this time.
Glasgow stuck to their bold game plan but a series of rucks that edged them close to the line ended with a bad knock-on by Ryan Grant. From the turnover, Cardiff motored back upfield, and it took another piece of defensive heroism, this time by Alex Dunbar, to knock the ball from Cuthbert's hands just he tried to ground it.
Again, though, Cardiff soon had more points, long-range specialist Rhys Patchell knocking over their second penalty from halfway in the 16th minute. Some lurid errors were starting to creep into Glasgow's game by that point, and the costliest of them all arrived at the start of the second quarter when Duncan Weir dropped a straightforward pass from Niko Matawalu behind the Warriors' try line. It was the platform the Blues needed. The impressive Robin Copeland charged off down the narrow side and when the No.8 was stopped, the Blues switched play back to the left. Cuthbert punched a hole through the middle and Patchell stormed up in support, scorching past Dunbar on his way to collect his try.
Halfpenny's conversion, and another penalty 10 minutes later, stretched Cardiff's lead out to 16-0, but the pattern at ground level was probably more worrying than the scoreboard. Errors had not so much crept into Glasgow's game as overwhelmed it, and they were horribly ineffective at the breakdown, where they turned over possession far too easily. The alarm bell was rung when Chris Fusaro, clearly furious, was taken off three minute before the break, his place taken by Tyrone Holmes.
Two minutes later, Glasgow finally strung a move together, attacking swiftly from a scrum on the Blues' 22. The ball was whipped to the right then slung back across the pitch, where Matawalu delivered the decisive touch with the pass that sent Sean Maitland over for a try.
But Glasgow could not build on that. Rather than take the momentum of the score into the second half, they surrendered control again and Cardiff took the initiative when Halfpenny clipped over another penalty seven minutes after the break. Glasgow did then enjoy one decent period of ascendancy, but all they took from it was two penalties by Weir. In light of what was to come, it simply wasn't enough.
Another Halfpenny penalty increased Cardiff's cushion and Cuthbert killed the contest with his interception and 80-metre run, holding off Ruaridh Jackson near the end of it. Leone Nakarawa did grab a consolation try for Glasgow at the finish but it was a score that had no significant impact on the bigger picture of the game and the tournament.