Heidel has been in the role for twenty years since being appointed as a mere 28-year-old in April 1992.

More recently, along with coach Thomas Tuchel, he has presided over the most successful period in the club's history, culminating in last season's fifth-place finish that brought European football to Mainz.

Mainz chairman Harald Strutz told the club's official website: "Christian Heidel is a stroke of luck for this club. I am able to promise I am never going to sack him.

"Which other club has a general manager that has such a huge connection with the club he is working for? And who else is that successful? We are very happy to have him."

Heidel, asked if he was happy to sign a new deal, added: "I have never discussed anything else.

"The way I am able to work and the way the authorities trust me at the same time. This is a pure joy to behold. I am very happy."