The jury has been out for the past few weeks but the verdict is looming. If Gregor Townsend's Glasgow side can hit their stride again and gallop off with the 1872 Cup then their RaboDirect PRO12 challenge will be back on track; if not, and especially if Edinburgh inflict two defeats, the season could become nothing more than a damage limitation exercise for the Warriors.
Scotstoun was a fortress for Glasgow last season, but its walls have crumbled over the course of three consecutive home defeats. And another tower toppled earlier this week when it was confirmed that Al Kellock will be missing for the next four months. Step forward, then, Chris Cusiter, who takes over the captaincy as Glasgow head for Murrrayfield and the first of their two festive clashes with their inter-city rivals.
Cusiter may not match Kellock's stature, but his competitive drive is the equal of any player's. And he is not remotely daunted by the burden of leadership. It has been said in the past, particularly in the Scotland context, that the responsibility can have an adverse effect on the scrum-half's game, but Cusiter rejects the suggestion outright.
"I have captained in a couple of games this year, games which have, in general, gone really well," he said. "Having that extra responsibility helps me get the best out of myself. It's something I enjoy.
"I feel for Al, because he has been unlucky with injury, but it all comes down to being an opportunity."
Not that Cusiter will have lost much sleep over the demands of the job. "You do try to give the team some direction, but apart from the coin toss that's about it," he explained. Yet there is, unquestionably, more pressure at the moment, for if ever a side needed a firm and decisive hand on the tiller it is Glasgow right now.
As the Warriors have lost just one of their past eight meetings with their Scottish rivals, the first part of that dusty old Tale of Two Cities line about the best and worst of times has more often applied to them in recent times. Yet, just as their results have charted worrying decline, Edinburgh's suggest a resurgence, victories over Gloucester and Leinster giving the men from the capital an overdue charge of self-belief. "They are looking like they are on good form just now with good wins behind them," Cusiter acknowledged. "We don't, so the tables are turned this year.
"There is pressure on us to get back to winning ways, but that is just the way things have gone. Edinburgh are flying high and have done really well to win away from home in England - that is a huge result - and then to beat Leinster at Murrayfield shows that they are confident and their system is starting to fall into place with the new coaches."
Yet, when the final whistle blows today, Cusiter will appreciate that the fixture has only really reached its mid-point. With the 1872 Cup decided on aggregate scores, the focus will have to be renewed ahead of the return leg at Scotstoun on New Year's Day. Cusiter appreciates how critical these two matches will be to Glasgow's season as a whole.
"There won't be much socialising after the first leg," he said. "We cannot afford not to play well at Scotstoun. We have lost three on the bounce there, which is just not acceptable. We have had a good run over the last few years but Edinburgh are the strongest they have been since I have been back [in Scotland]. It will be a tough game."
As always, with Scotland places at stake as well, there will be fascinating individual contests, but Cusiter makes light of his own duel with Greig Laidlaw, the Edinburgh scrum-half who is also currently first choice for Scotland as well.
Cusiter said: "It is always a good match-up. We know each other very well and I'm looking forward to taking him on again. We are very different players, with different strengths and styles. He has been playing well in the last couple of games I have watched, so it will be a good challenge. But I am there to play well for Glasgow, and to win the game for Glasgow. That is my focus. I can't change my game because I am playing against a certain scrum-half. I want Glasgow to win and will do everything I can to help them win.
"Anyway, at scrum-half you very rarely get a direct one-on-one with your opposite number. Maybe as a winger or a centre you will get more chances for that, and in the scrum there are big battles, but scum-half is different. It is more about controlling the team tactically and getting the forwards to work the way you want them to. That is my challenge. It does not really affect me that Greig is playing."