Barcelona faces its worst nightmare in the third matchday of this season's UEFA Champions League: Bayern Munich, the Blaugrana's most formidable European foe.

Despite a promising start to the season, with Barça leading LaLiga EA Sports and winning ten of their twelve games across all competitions, they now face a crucial week that will test their mettle in major matches. First, they take on the Bavarians, followed by a clash with Real Madrid this coming Saturday.

On paper, Bayern Munich is the last team Barcelona would want to face. Out of their 15 encounters, Barça has only managed two wins, two draws, and suffered 11 defeats. More alarmingly, the last five meetings have ended in losses, with a cumulative scoreline of 2-19 against the Catalans, who haven’t beaten Bayern since 2015.

Among all these defeats, none was as painful as the 2-8 thrashing in the 2019-20 Champions League quarter-finals. Four years later, Barcelona, now led by Hansi Flick, only has two survivors from that disastrous night in Lisbon: the injured Marc-André ter Stegen and midfielder Frenkie de Jong.

Flick has quickly transformed the team, instilling the same aggressive, high-pressing, and vertical playstyle that defined his Bayern side. At the forefront is Robert Lewandowski, with 14 goals in 12 matches, who is now leading Barça's attack.

Müller: The face of Barça's torment

If any player personifies Bayern’s dominance over Barcelona, it's Thomas Müller. The German forward, Bayern's all-time appearance leader, has scored 8 goals in 9 games against the Spanish side, often sealing or emphasizing the most brutal defeats.

After one of those matches, Müller remarked: "Barça can't handle the intensity. They have everything, technically and tactically, but they can't compete at the highest level." He even tweeted his personal stats against Barça with the provoking caption, "I love playing against Barça."

While Müller is likely to start from the bench as a super-sub in this Montjuïc showdown, his mere presence is enough to irritate Barcelona fans.

When the draw paired them with Bayern two months ago, Müller expressed his delight at facing Hansi Flick's team. It remains to be seen what sentiment he’ll carry after this meeting between the current leaders of Spain and Germany.