The Argentine's Bundesliga honeymoon lasted barely a week. Leipzig thrashed Borussia Mönchengladbach 3-0 on the opening weekend of Demichelis's reign, but were then thoroughly outplayed in a 1-3 defeat at Werder Bremen, prompting Bild to report "considerable concerns" inside the club over whether he has the right approach for the team's style of play.
Demichelis took over in the summer after Leipzig sacked Ole Werner, despite the German having led the club to a third-place Bundesliga finish and a return to the Champions League in his only season in charge.
RB Leipzig reportedly triggered a release clause to land the former Bayern Munich defender from relegated Spanish side RCD Mallorca, where he had managed only twelve games. He had previously worked in Mexico and Argentina with CF Monterrey and River Plate respectively.
Sporting managing director Marcel Schäfer did not hide his frustration after the Bremen defeat, calling it "a real wake-up call" for the squad.
"Our occupation of the box was not good enough. Against an opponent sitting very deep, we found too few solutions," he said.
"We do not need to single out individual players, I expect a clearly different performance. With our own standards, we cannot simply brush this game aside."
Leipzig were missing six potential first-team regulars through injury and absence at the Weserstadion, including Brajan Gruda, Roko Reitz and Castello Lukeba, though the club's hierarchy have been reluctant to accept that as a full explanation for the performance.
The club's much-discussed pressing system, central to the "Intensity is our Identity" motto displayed at their training ground, was singled out as an area of particular concern following the defeat.
Behind the scenes, concerns about Demichelis's tactical ideas with the ball are said to have existed since pre-season, adding early pressure to a managerial reign that is still only a handful of matches old.
Leipzig will also be without the returning Gruda and Lukeba for a little while longer, though both are expected back on the pitch soon, offering some hope that results can improve before the pressure on the Argentine intensifies further.