Schalke slumped to a shock 3-0 home loss to relegation-threatened Augsburg on Sunday, their fourth defeat in five games dropping them to eighth place in the Bundesliga.
Schalke struggled to launch decent attacks and a first-half chance which fell to Rabbi Matondo was the closest they came to scoring.
Despite having 67% possession, the Royal Blues managed only two shots on target in the match.
The defeat piled more pressure on coach David Wagner, whose team have scored only two goals in their last nine games.
"We are not dangerous enough and our conversion rate is not good either," Wagner said. "Then we also make mistakes that lead to goals. These are all things we need to work on.
"It is also a mental thing and the current situation does not go past the boys without leaving a trace.
"Now it is about supporting the boys so they can play football again with more confidence."
Schalke, now without a win in nine league games, slipped down to eighth place on 37 points while Augsburg's first victory after four straight losses lifted them to 12th on 30, seven above the relegation playoff spot.
The Bundesliga became the first major sports league to resume last week, with no fans in attendance, after being suspended for more than two months due to the COVID-19 pandemic.