Frankfurt routs 10-man Bayern 5-1, fireworks in Berlin derby
Kovac, who coached Frankfurt to a German Cup win over Bayern in 2018, saw his former side end its 16-game winless run against the Bavarian powerhouse.
"Even with one player less, you shouldn't lose 5-1 here. It's disappointing," said Kovac, who is coming under increasing pressure after a series of disappointing performances.
To questions about his future, he said, "How I feel is not important. The ones who decide are the ones who should be asked."
Bayern's Jérôme Boateng was sent off in the 10th minute for bringing down Gonçalo Paciência as the last defender. Referee Markus Schmidt initially awarded the home side a penalty after Paciência fell in the area, but changed it to a free kick after consulting video replays.
Filip Kostic scored in off the far post in the 25th, and Djibril Sow made it 2-0 after more speedy Frankfurt play nine minutes later.
But Bayern can still count on Robert Lewandowski. The Poland striker showed all his prowess to elude two defenders with a turn before prodding the ball past Frederik Rönnow in the 37th.
With that, Lewandowski extended his Bundesliga record of scoring in the first 10 league games.
It leaves Bayern four points behind league leader Borussia Mönchengladbach, which stayed one point clear with a 2-1 win at Bayer Leverkusen.
FIREWORKS IN BERLIN
Sebastian Polter's 90th-minute penalty gave Union Berlin a 1-0 win over Hertha Berlin in the German capital's first Bundesliga derby featuring teams from either side of the formerly divided city.
Referee Deniz Aytekin, who had earlier suspended play due to fireworks, pointed to the spot after Hertha defender Dedryck Boyata was penalized for a foul on Christian Gentner.
Polter duly scored from the spot but the home fans' celebrations were delayed through 10 minutes of injury time due to the earlier interruption caused when fireworks from Hertha fans landed on the pitch.
Hertha fans fired more fireworks onto the pitch when the game ended.