Lothar Matthaeus, the former head coach of Bulgaria's national football team, has described his work in charge of Bulgaria as his "biggest mistake".

The German football legend has slammed the head of the Bulgarian Football Union, Borislav Mihaylov, and the leadership of the BFU in general.

"During my work with the team I ended up in many unpleasant situations. In August 2012, for example, after we lost 1:0 to Belarus in Minsk, several players broke the curfew," Matthaeus told the Presa daily, referring to one of the major scandals in Bulgarian football in the recent years.

"However, they were not punished at all because they were under the protection of BFU President Borislav Mihaylo. That's why they could afford to drink in bars, and to have fun with women before an important match," the German coach revealed.

He said he tried to remove striker Ivelin Popov and some other players from the team as a punishment but he was not allowed to.

"I can say that the Bulgarian football federation still owes me money under the contract. Apparently, documents mean nothing for those in charge of Bulgarian football. I can't understand how Mihaylov can be elected to the management structures of UEFA," Matthaeus said.

He also slammed the Bulgarian Football Union for organizing an "absurd" friendly with Estonia, instead of getting a match in the UAE.

"I deem my work with the Bulgarian national team the biggest mistake in my career," Matthaeus concluded.