But Gordon Strachan's side left Croatia without control over their own destiny. By then, Belgium had already recorded a vastly superior goal difference and, even if Igor Stimac's team went on to defeat both them and Serbia, they still would have ended up relying on their main rivals' dropping points.
However, as it soon transpired, taking away three precious points was not the worst thing Scotland did to Croatia. With that surprise defeat, Strachan's men also dented their confidence. For Modric, Mandzukic and co, who were a top-10 team in the world according to FIFA rankings at the time (and remarkably still are), it was all downhill after that match.
It is not as if the signs had not been there. The team rarely played well in the qualifiers and were very lucky to scrape through in most games. Cracks appeared everywhere and analysts warned of various flaws and weaknesses, but coach Stimac and his players were able to hide behind a facade of good results, hitting back at critics for creating a 'negative atmosphere' when they appeared to be marching towards Brazil at a steady pace.
Stimac, in particular, grew more and more arrogant towards the press after beating Serbia at home and overturning a deficit in Wales in the last 15 minutes of the match with a show of chaotic, gung-ho football. He assumed an almost messianic role, claiming his mission was to 'awake' Croatia - not just the team, but the whole nation. He also began to experiment with tactics, slowly abandoning his predecessor Slaven Bilic's tried and tested approach.
And then they hit the wall against Scotland. Stimac attempted to press high with a 4-4-2 midfield diamond, only to relinquish control in the middle. As the Maksimir Stadium echoed with the noise of the Tartan Army boys, Croatia finished with as many as four strikers, but to no avail. They were outmuscled and outwitted by Scotland, who fully deserved their unexpected win.
Severely criticized by both the media and fans, Stimac embarked on a series of tactical tinkerings which only made things worse. While the defeat in a friendly against Portugal four days later - playing a 4-2-3-1 - surprised nobody, Croatia genuinely struggled to overcome Liechtenstein in August, scoring five minutes from time to make it 3-2. In that game, the coach deployed a different version of the 4-4-2, with no holding midfielder and a striker on the wing.
Last month, he used a 4-3-3 shape against Serbia - a game that many branded as Stimac's worst showing - yet Croatia somehow managed to snatch a point, scoring from what was their only chance. Four days later, it was a 3-5-2 as a team of second-stringers defeated South Korea 2-1. Most recently, against Belgium last week, Croatia took to the field in what Stimac announced as 3-4-2-1, but essentially was a team with five defenders who moved high up the pitch when in possession. Belgium scored both of their goals on quick counters, after winning the ball in their own half (first goal) or even in their box (the second one).
That's five different systems in five matches - six in six, if you count the Wales game, when Stimac fielded a fairly classic 4-4-2. No wonder he's been sarcastically nicknamed 'The Alchemist' by some sections of the media. And yet his approach against Scotland remains anyone's guess.
During a press conference ahead of the Belgium match, one visiting reporter tried to provoke Stimac. "How does it feel," he asked, "when nobody in the country likes you?" After initial confusion, the coach replied with a counter attack: "You spoke to four million people so you can claim that? Or are you just following what some people are writing?" But the reporter was not far from the truth. 24 sata, the best-selling daily newspaper in Croatia, ran an online poll the day after the match: 97% of the participants said Stimac should leave.
He has never enjoyed popular support, mainly because people are well aware that he was not installed for his expert credentials (he has very limited coaching experience), but seized the post through a pact with Zdravko Mamic, Dinamo Zagreb's chairman and shadow ruler of Croatian football. Stimac, who previously posed as Mamic's sworn enemy and attempted a coup which would have made him the Croatian FA president, has never tried to deny that, instead saying that people who mention it "don't see the forest for the trees". What he always claimed, though in not so many words, was that his opportunism is in the best interest of the nation.
Meanwhile, the fans became alienated - there were just 12,000 at the Maksimir against Belgium, and at least 2000 were cheering for the away team - and even some players have raised their voices, albeit tentatively. "I don't think we played a single game as well as we should in this campaign," captain Darijo Srna stated. Luka Modric added: "We've had too many players out of their ideal positions." Ever true to his macho, autocratic self, Stimac replied: "I wish my players would worry less about setting up tactics and more about carrying them out."
When Croatia played Scotland in June, they were a team seemingly full of faith in themselves. Davor Suker, the FA president, said he expected them to improve their goal difference and win by four or five goals. Heading into the rematch, the situation could not be more different. Sure, only an astonishing combination of results would prevent Croatia from qualifying for the play-offs, but they are now in complete disarray; a team bereft of confidence and popular support, just trying to get through this game before their two-legged decider. And Scotland proved to be their undoing.