Six of Celtic's upcoming seven fixtures are away from Celtic Park.
With the Europa League behind them, Celtic now face a campaign-altering two-week spell.
By 14 March, they might be cruising in the title race with the momentum on their side and into the Scottish Cup last four.
Alternatively, they might find themselves further toiling to retain the championship and staring at a trophyless season.
The first stop is a trip to Ibrox on Sunday for a massive league clash, with Celtic behind Rangers by a couple of points having played one game fewer, with Hearts six clear of the champions.
This is followed by a journey in midweek to Aberdeen, before heading back to Ibrox in the Scottish Cup last eight and then welcoming in-form and formidable Motherwell.
Six of their next seven fixtures are away from Celtic Park. This often-criticized Celtic squad is set to be stress-tested after a chaotic first two-thirds of the season.
"We can expect a lot of surprises and changes," stated a former Celtic defender. "It wouldn't shock me if the league goes to the final day. But they must prove themselves over the coming handful of games. You have to be relentless, otherwise they will not win the trophies."
O'Neill Now Has Selection 'Dilemma'
Although the victory over Stuttgart proving moot in Celtic's bid to reach the knockout stages of the Europa League, it could yet prove important.
The manager rotated eight of his starting line-up and some of the squad members put in impressive displays to secure the club's first ever win in Germany.
Luke McCowan stroked home the decisive goal after just 28 seconds and played positively, while in the back four, Dane Murray stood out in a gutsy display.
Murray especially made his case to start next to Liam Scales. One magnificent defensive intervention was notable and he was assured when dealing with set-pieces.
But the most talked-about performance was saved for back-up goalkeeper Viljami Sinisalo as he played his part in a first Celtic clean sheet in six matches.
The established goalkeeper has been under heavy criticism after a series of errors. The Finnish was called upon and made six saves, in a display labeled "flawless" by a former Celtic midfielder.
A former Celtic goalkeeper believes Sinisalo performed well enough to start against Rangers on Sunday.
"He had some excellent saves and looked composed when he had the ball and read the game well," he said. "It's a big decision to make at the weekend. Based on that showing, I would be giving him the nod. Give him a run in the team now."
The Celtic manager agreed that several players have given him "food for thought".
"[Sinisalo] was outstanding in the game, really well. 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 Test Lies Ahead
The additional positive of Celtic's win was that they showed they can grind out a victory.
Historically, Celtic have arrived and naturally looked to control possession from the first whistle to the last against every Scottish rival.
But this more fragile side had looked more and more susceptible in recent times, often conceding more than one goal per game.
Having not won at Ibrox in four attempts and considering Rangers have won their past 10 home matches, a show of resilience in Germany was well-timed.
Might Celtic take a somewhat more cautious approach? Right now, it is solely concerning winning.
"You don't have to have all the possession to win the game," observed an analyst. "You've got to put in the effort, defend well, get a bit of luck and have a reliable shot-stopper."
"Celtic have not played well this season, but they are still in contention [in the league]. They still have a chance, with a match to spare. The players will take great confidence from tonight - the weekend will be a decisive one."
