Six of Celtic's next seven matches are outside of home.
With the Europa League behind them, Celtic are now staring down a season-defining two-week spell.
Come mid-March, they could be motoring in the league with the momentum on their side and into the Scottish Cup semi-finals.
Alternatively, they might find themselves still struggling to retain the championship and staring at a trophyless season.
The initial challenge is a trip to Ibrox on Sunday for a titanic league encounter, with Celtic trailing Rangers by two points after playing one game less, with Hearts six clear of the title holders.
Then it is a midweek trip to Aberdeen, before returning to Ibrox in the Scottish Cup quarter-final and then welcoming in-form and formidable Motherwell.
Six of their following seven fixtures are away from Celtic Park. This much-maligned Celtic group is about to be put under severe pressure after a chaotic first two-thirds of the season.
"There will be a lot of twists and turns," commented a ex-Celtic player. "I wouldn't be surprised if the league goes to the final day. But they must prove themselves over the coming handful of games. You have to be utterly consistent, or else they will not win the trophies."
O'Neill Now Has Selection 'Dilemma'
Although the victory over Stuttgart being ultimately irrelevant in Celtic's bid to reach the knockout stages of the Europa League, it could still turn out to be important.
The manager rotated eight of his first eleven and some of the squad members put in impressive performances to claim the club's first ever win in Germany.
Luke McCowan calmly slotted the winner after just 28 seconds and was a positive influence, while in the back four, Dane Murray stood out in a gutsy performance.
Murray especially stated his claim to start alongside Liam Scales. A superb block was notable and he was assured when defending corners.
But the most discussed performance was delivered by second-choice goalkeeper Viljami Sinisalo as he played his part in a long-awaited shutout in half a dozen games.
The first-choice goalkeeper has faced intense scrutiny after a series of errors. The Finnish was called upon and made several crucial stops, in a display described as "perfect" by a club legend.
A former Celtic goalkeeper is of the opinion Sinisalo performed well enough to start against Rangers on Sunday.
"He had some very good saves and looked calm when he had the ball and had good anticipation," he said. "It's a big decision to make at the weekend. On that performance, I would be starting him. Give him a run in the team now."
The Celtic manager conceded that several players have given him "plenty to consider".
"[Sinisalo] played brilliantly in the game, exceptionally. He's the talk all round the dressing room," the manager commented. "He's got a lot of talent."
Viljami Sinisalo staked his claim to start against Rangers on Sunday.
'Critical' Rangers Challenge Awaits
The other benefit of Celtic's win was that they demonstrated they can battle to a victory.
Historically, Celtic have arrived and typically sought to control possession from start to finish against every Scottish rival.
But this more fragile side had looked more and more susceptible in recent times, often letting in more than one goal per game.
Without a victory at Ibrox in their last four visits and considering Rangers have won their last ten home matches, a show of resilience in Germany was well-timed.
Could Celtic take a somewhat more cautious approach? Right now, it is all about winning.
"You don't need to have most of the ball to win the game," observed an analyst. "You've got to put in the effort, be solid at the back, get a bit of luck and have a good goalkeeper."
"Celtic have struggled for form this season, but they are hanging in there [in the league]. They still have a chance, with a game in hand. The players will take great confidence from tonight - the weekend will be a decisive one."
