The coach who led Greece to a shock Euros win in 2004 insists Jurgen Klopp could manage any team he wants in the future.
The Liverpool boss has the Reds on track to win the league for the first time in 30 years by a mammoth margin on the back of their sixth Champions League title last season.
And Otto Rehhagel believes the world is Klopp's oyster.
'Jurgen's career is unique, just wonderful,' he told Bild. 'I was worried that he would not lose a football game!
'Jurgen can inspire his players - and Liverpool has a lot of money. But he has also made the right choices with the players he has signed.
'I can't say where his career will end. He is still young and he will grow. The English championship is now important to him. He can do anything in the future.
'He could be the national coach, coach at Bayern - anything he wants. All doors are open to him.'
Klopp's next match in charge of Liverpool is West Ham at Anfield on Monday night.