Deyovaisio Zeefuik's fourth-minute screamer sparked a breathtaking first-half performance which gave Hertha hope in the relegation fight and dealt another blow to Leverkusen's hopes of European qualification.
"It's a very disappointing result, because we had high hopes of winning this game," said Bosz after his side slumped to a third defeat in four games. Asked whether he thought he would still be in a job by the end of the upcoming international break, the Dutchman replied: "Yes".
Bosz's team were top of the table in December but are now seven points adrift of the Champions League places after a dramatic collapse in 2021.
Hertha, meanwhile, hauled themselves out of the bottom three with Sunday's win, returning to form after just one win in their previous 11 games. "I told the boys at the start of the week not to look at the newspapers or the TV because we were going to go into the game in the relegation zone," Hertha coach Pal Dardai told Sky. "In terms of the table and our mood, this was a hugely important win."
In Sunday's late game, second-half goals from Roland Sallai and Philipp Lienhart sealed a 2-0 win over Augsburg to keep Freiburg in the race for Europe.
The win saw Freiburg jump to eighth, just three points adrift of Leverkusen.