Bayer Leverkusen fired Sami Hyypia as coach after an alarming run that has put Champions League qualification in doubt.
Youth coach Sascha Lewandowski has been put in charge to the end of the season.
What he and his coaching staff achieved with the team in the first half of the season was well beyond expectations and earned him praise from all sides.
The Bundesliga club said in a statement that former Liverpool defender Hyypia was being released 'with immediate effect', following Friday's 2-1 loss at relegation-threatened Hamburger SV.
Leverkusen previously drew with bottom side Eintracht Braunschweig and are in danger of losing fourth place, with both Wolfsburg and Borussia Moenchengladbach in a position to overtake in the next round of matches.
Leverkusen were second at one point in the Bundesliga but had a severe change in fortune after the winter break with only three wins from 12 league games this year.
They have also endured humiliating losses to Paris Saint-Germain in the Champions League and second-division Kaiserslautern in the German Cup.
"What he and his coaching staff achieved with the team in the first half of the season was well beyond expectations and earned him praise from all sides," Leverkusen sporting director Rudi Voeller said.
"The dramatic events of the last few weeks leave us no other choice but to bring about a separation. We want to and have to try everything to save the season."
Assistant coach Jan-Moritz Lichte was also released.
"It's not an easy situation for me now to take Sami's place," Lewandowski said.
"We had responsibility for this team together for more than a year. So you can't take over without regret that the former partner couldn't realise his dreams."