Heading into Euro 2016, defence seemed to be the greatest obstacle standing between Joachim Low's Germany and victory in France.
Die Mannschaft were hemorrhaging goals, with their 2-0 win over Hungary in their final pre-tournament warm-up friendly marking their first clean sheet in nearly a year. The last time they had held opponents scoreless had been in a June 13, 2015 match against Gibraltar, who only played their first recognised international match in late 2013 and are not yet FIFA members.
Over the past year, Germany have had days in which their attack was on and days in which it stuttered. They conceded twice to Scotland last September yet managed to come out victorious. Yet a month later, Ireland did enough to hold the 2014 World Cup winners scoreless over 90 minutes en route to a narrow 1-0 win.
There was no doubting the quality among superstars like Thomas Muller, Mesut Ozil, Marco Reus and Mario Gotze, but the Germans were so poor at the back that there was good reason to question whether they would stand a chance at winning Euro 2016 just by outgunning their opponents. After all, in the year prior to the tournament's opening kick, Germany had lost to the United States, Ireland, France, England and Slovakia.
Three of those defeats came in the last five matches preceding the competition, during which Die Mannschaft's defense conceded a whopping nine goals. Surely, it seemed, Germany's only chance at winning Euro 2016 was to hope the attack was at its sharpest for seven consecutive games.
Yet at the end of their group-stage campaign, the narrative of Germany's Euros has been entirely different from what had been expected. It's been a low-scoring tournament, yet at the time of their clinching first place in Group C, only Poland were able to match Germany's record of three games without conceding. The only other side not to have conceded by Wednesday morning was Italy, with their group (E) as well as Group F yet to conclude their final round of matches.
Overall, Germany's attack has been quite poor. They were held scoreless against Poland, while it took a header from Shkodran Mustafi to put them ahead against Ukraine. Bastian Schweinsteiger added a second against Mykhaylo Fomenko's side, but it came as Ukraine were desperately chasing an equaliser.
Germany were much better against Northern Ireland in the final group-stage game, at least in terms of creating chances, yet they only managed to score once.
Putting the ball in the net just once would not have been enough for Germany to win in the vast majority of their games in the year prior to Euro 2016. It more often would not have been enough to even avoid defeat. Germany won against Northern Ireland and took the group not for their outstanding attack but rather their exceptional defence.
At the core of it were, predictably, Bayern Munich's star players.
Jerome Boateng was unsurprisingly at the heart of the German defence for all but the last quarter-hour of the group stage. Perhaps the single greatest beneficiary of Pep Guardiola's tenure in Munich, the former Manchester City and Hamburg man has had a magnificent tournament thus far.
There has been plenty of commentary on how Robert Lewandowski has yet to put a single attempt on target during the Euros, per UEFA, but part of that comes down to exceptional defending by the German side. Boateng in particular made a remarkable recovery to deny his club teammate as the Polish striker looked to pull the trigger.
Low and Co. will hope for a quick recovery from the 27-year-old, whom the trainer revealed after Wednesday's match had been substituted due to a calf muscle injury, per Goal.
Alongside Boateng, new Bayern recruit Mats Hummels has also been outstanding. The pair seem to complement one another perfectly, and Hummels hit the ground running as he made his return to the starting lineup for the Poland clash.
Two full matches after returning from injury, he looks to be at the peak of his game, a continuation of the form he showed for Borussia Dortmund all season. Confidence is key for defenders, and the 27-year-old seems to have it in abundance following an excellent campaign with BVB and his transfer to Bayern.
Finally, it's worth noting that Germany have benefited from a third Bayern man in defence, even if he isn't exactly a defender by natural position: Joshua Kimmich.
The 21-year-old replaced Benedikt Howedes for the Northern Ireland match and was able to do much more than the Schalke man ever could have in supporting Muller on the wing. The attacker benefited significantly and looked more dangerous than before, and Kimmich still managed to take care of his defensive duties.
Howedes himself admitted on his Twitter account (in German) that Low's decision to play Kimmich over him was the right one, and it seems the youngster will continue to start in the knockout rounds.
Kimmich is a natural holding midfielder and may not spend much of the upcoming campaign in defence. But he still is yet another example of a Bayern player who has become a key part of Germany's elite rear guard. Of the back five who started against Northern Ireland, four were Bayern players.
Kimmich may be new to the German defence, and it's unclear what role he'll play at club level next season. If Hummels' and Boateng's form for Germany is any indicator, however, they will be an absolutely elite combination at the back for Bayern in the coming years.
The former's anticipation and tackling skill, paired with the latter's pace and mentality to never be fazed by the big stage, could turn a brilliant Bayern defence into one of the all-time greats. And with Manuel Neuer behind them, opponents might as well try to plough through a brick wall.
The three have already won a World Cup together; the next step is the Euros, then perhaps the Champions League with Bayern.