Niko Kovac had a post-match plan on returning to Berlin, the city of his birth. After bumping into some familiar faces at the Olympiastadion, where his team played Hertha, he was going back to the team hotel and meeting up with various friends and relatives for a low-key drink and dinner. When you’re coach of Bayern Munich, life has its share of certainties, one assumes. It’s safe to project ahead.

By the end of Friday, Kovac was probably less in the party mood. His old teammate Pal Dardai’s side handed the champions their first defeat in a competitive fixture under their new coach, and it capped a strange and confusing four-day spell for Bayern. In a rare show of vulnerability, they had dropped five points and given the nation’s neutrals – which, such has been Bayern’s iron grip on the Bundesliga since 2012-13, is a group even wider than it might have been in other eras – the merest sniff of hope that some title titillation might be on the horizon.

“Will it be exciting this season?” Bild asked with wide-eyed longing on Sunday morning. After six successive seasons of Bayern cruising to the title with a level of dominance notable even by their storied standards, most outside the red half of Munich will readily grasp any excuse to believe in the possibility of change.

Hertha’s win opened that door by giving the league’s other two unbeaten sides, Werder Bremen and Borussia Dortmund, the chance to end the weekend at the summit – Werder blew their opportunity at Stuttgart before Dortmund belatedly took theirs in a topsy-turvy game in Leverkusen on Saturday. For now, six games into the campaign, the table is anecdotal, but the route taken to this point is of great interest.

The midweek slip against Augsburg could be brushed off pretty easily. Missed chances, over-dominance, sleepwalking, a freak occurrence. You can call it what you like, but it felt like an accident, something that wouldn’t happen again were the situation replayed a thousand times. Now, tacked on to defeat in the capital, it feels like it might be more than that.

Kovac had a point when he said “if we make the most of our opportunities, then the performance would be valued differently”, but to hear Manuel Neuer suggesting “luck comes back around” didn’t sit well. Few would blame Tuesday’s Champions League opponents, Ajax, for arriving at the Allianz Arena with some trepidation before encountering a sore Bayern, but it didn’t feel as if there was quite enough acknowledgment of fault here.

There was plenty of it to be recognised (as well as another sterling performance by Hertha, recovering from their own first loss of the season at Werder), especially in a first half during which Bayern, and especially Jérôme Boateng, lost all sense of defensive orientation. The centre-back conceded the penalty from which Vedad Ibisevic opened the scoring, “sliding across the turf with the elegance of a broken vacuum cleaner” according to Süddeutsche Zeitung, as he aimed to dispossess Salomon Kalou.

For the second, eventually tucked away by the in-form Ondrej Duda, Boateng was left floundering by Valentino Lazaro’s lusty burst to the touchline before the right-back provided the decisive pass across goal. A sanguine Kovac conceded after the game that Boateng needed to do better. The Germany defender, one of Bayern’s core who endured a chastening summer in Russia, has received all the coach’s faith so far, despite having openly flirted with a move to PSG in the summer. This was a first public rebuke.

Bayern Munich’s French midfielder Franck Ribéry, right, and Hertha Berlin’s Dutch defender Karim Rekik vie for the ball. Photograph: Odd Andersen/AFP/Getty Images

If that was symptomatic of Bayern’s first-half imprecisions, during 45 minutes in which they were second best and often careless in possession, then it was the display after the interval that could really be the basis for medium-term concern. It wasn’t terrible and the visitors put a shift in, but it lacked the requisite spark. Stand-in Hertha goalkeeper Thomas Kraft – who left Bayern in 2011 after making a handful of first-team appearances and only played because of first-choice Rune Jarstein’s injury – was not tested nearly as often as he might have been. The visitors had 25 efforts at goal and almost 70% possession but it never felt as if Kraft, nor Hertha, were truly under the pump.

The feeling that Kovac’s squad looks a bit thin has never been more acute after a busy week. Bayern fought but looked tired, with none more so wan-looking than Arjen Robben. Uli Hoeness talked about saving up to make a big splash in the 2019 summer window and even if – as expected – Bayern do go on to retain their title, this period has served to remind that a major squad overhaul is due.

All is not lost, of course. Whichever way you judge Bayern’s stumble, there’s little disputing they’re in a better place than they were 12 months ago, when the Carlo Ancelotti era came to an abrupt end after a Kylian Mbappé-designed thrashing at PSG. Yet Hertha have at least given the other 17 cause to daydream after an unusual week.

Talking points

• Dortmund, then, lead the Bundesliga after that remarkable comeback. They trailed 2-0 and Heiko Herrlich’s side were close to finishing the job on the counter but once again, Lucien Favre’s bench came up trumps, with Paco Alcácer scoring twice and Jadon Sancho providing another two assists as they finished 4-2 winners. The English teenager has now been involved in a goal every 21 minutes so far this season (it’s once every 17 for Alcácer, albeit based on a smaller sample size). Marco Reus’s equaliser, showcasing the burgeoning partnership between him and Sancho, was scintillating, with the ball going from Roman Bürki’s hands to the back of Leverkusen’s net in 14.92 seconds. “We’re lucky to have such an ace up our sleeve,” purred Dortmund’s captain.

Dortmund’s Paco Alcacer, top, celebrates with Achraf Hakim, front, and Jadon Sancho after scoring his side’s third goal. Photograph: Rolf Vennenbernd/AP

• A win, at last, for Schalke, who beat Mainz 1-0. Domenico Tedesco showed little reaction to Alessandro Schöpf’s winning goal but his emotional outpouring at the whistle – by which time Die Königsblauen were hanging on – was in stark contrast and showed how much this was needed. Schalke had been desperate for the worm to turn and were trying everything – a quick sweep along Schalke’s bench at full-time by the cameras clocked a lucky one cent coin left on each seat.

• Far more openly angsty was Tayfun Korkut, almost literally tearing his hair out at various stages of Stuttgart’s first win of the season, over Werder Bremen. They came back from conceding “the slapstick goal of the year,” as described by Das Aktuelle Sportstudio, via Ron-Robert Zieler’s hapless own goal, with Gonzalo Castro’s first goal for the club winning it.

• It was the Julian Nagelsmann derby in Sinsheim, as current club Hoffenheim took on his future side RB Leipzig. He was partly put in his place after some perceived pre-match chip at Ralf Rangnick (“My boss? He’s my supervisor, at most”) by the visitors’ win, secured by Youssef Poulsen’s brace.

