There were signs of tension at Bayern Munich even before the Bundesliga powerhouse fell to their first defeat of the season, losing 3-1 at lightly regarded BATE Borisov in the Champions League.

At home, Bayern are off to a perfect start with six wins from six matches, but sporting director Matthias Sammer still found fault with the team’s performance, drawing the ire of veteran coach Jupp Heynckes (photo).

The unexpected defeat against BATE this week only highlighted the differences, although both men tried to present a united front after the team’s return from Belarus.

Bayern President Uli Hoeness defended both men and said their differences were exaggerated by the media.

It remains to be seen how the team will react in the Bundesliga today against Hoffenheim.

In the previous round, Bayern scored two late goals to win 2-0 at Werder Bremen, prompting Sammer to criticise the performance as “soggy,” among other attributes.

Heynckes responded by saying the criticism was unjustified and that he could not agree with it, saying such discussions were better left behind closed doors. He also said accused Sammer of “populism.”

Sammer was lured over from the German football federation in the offseason to jolt a team that had not won a title in two seasons, an eternity in Bayern’s terms.

He immediately took an active and public role in Bayern, attending every practice and sitting on the bench at every match. Many wondered how the fiery Sammer would get along with Heynckes, the 67-year-old even-tempered coach and a man of understatements.

Hoeness, a friend of Henyckes who persuaded the coach to return to Bayern, said Heynckes was doing a “super job” but that it was Sammer’s job to criticise.

Hoeness said Sammer’s criticism was justified and that Heynckes had to accept it.

The president described the differences between the two men as “little problems” blown out of proportion by the online media but advised them to settle any problems privately.

The loss in Belarus ended Bayern’s run of nine consecutive wins in all competitions and prevented them from setting a club record for best start to a season.

There was more bad news for Bayern this week when the team’s doctor said he could not predict when striker Mario Gomez would return after ankle surgery. His replacement Mario Mandzukic tops the league with six goals, though, and Bayern have so far overcome the absence of Gomez, their top scorer over the past two seasons.

Hoffenheim come to the Allianz Arena still recovering from the shock of having their midfielder Boris Vukcevic in critical condition after a car crash.

Bayern are seven points ahead of Borussia Dortmund, but the defending champions have moved into third place with a 5-0 win at Moenchengladbach.

Dortmund, who were unlucky to get only a 1-1 draw at Manchester City in the Champions League, don’t play until tomorrow, when they visit Hannover.

Eintracht Frankfurt, who are two points behind Bayern, travel to Moenchengladbach tomorrow.