Mainz sacked Sandro Schwarz as head coach on Sunday after more than two years in charge, making him the third boss to be dismissed by a Bundesliga club in the last week.
Schwarz, 41, was shown the door after Saturday's 3-2 home defeat to newly-promoted Union Berlin which followed last week's 8-0 drubbing at high-fliers RB Leipzig.
Schwarz's dismissal comes after Achim Beierlorzer was sacked by Cologne on Saturday, and Niko Kovac was let go by Bayern Munich last weekend.
Defeat to Union saw Mainz drop into the bottom three after losing eight of their first 11 league games this season - the worst start to a season in the club's history.
Mainz now have a fortnight to find a new coach during the international break before their next game on November 24 at Hoffenheim, who are fourth after winning all of their last six games.
Sandro Schwarz has become the third Bundesliga coach sacked within a week after Mainz showed him the door on Sunday.