Schalke 04 fans on Sunday called for coach Jens Keller to be fired after just 51 days in charge in the wake of the Royal Blues' "humiliating" 2-1 home defeat to Bundesliga bottom side Greuther Fuerth.
Banners reading "Keller Out!" greeted the 42-year-old when he arrived at training in Gelsenkirchen on Sunday having only taken charge on December 15 when Huub Stevens was sacked after just 15 months at the helm.
"The result is a disaster and humiliating," admitted general manager Horst Heldt.
"That was a major setback, as we had already planned on having the three points."
Having been second in the Bundesliga, Schalke are down to sixth in the table with just one win in their last eight league games and are away to Galatasaray in the Champions League last 16 on February 20.
"We are hugely disappointed. After such a defeat, we do not need to talk about the Champions League," Keller said dejectedly after Fuerth ended their their 17-match winless streak in Gelsenkirchen on Saturday.
Fuerth broke Schalke's hearts with a 92nd-minute winner from Serbia's Nikola Djurdjic.
Having been held to a goalless draw at second-from-bottom Augsburg the week before, Schalke are at Bundesliga leaders Bayern Munich on Saturday.
Heldt has said Keller's role is safe for now: "we're not planning with anything else", but Schalke's lack of organisation and fighting spirit was clear for all to see.
With playmaker Lewis Holtby having been sold to Tottenham Hotspur, new arrival Michel Bastos capped an impressive debut with a goal after signing from Lyon but the Brazilian alone can not carry the Royal Blues.
"Everyone has to ask himself where is the missing few percent in the crucial situations," added Heldt.
"Jens has a little credit, he is doing a good job, even if the hard results are saying something different. It is clear the tough discussions will come and they will only get harder.
"I won't be pulling myself out of my responsibilities."