Both sides clash at Hampden Park in Scottish Cup action next week.
The former defender questions whether they can be successful without spending money.
Didier Agathe believes it would be 'fantastic' if Aiden McGeady returned to Celtic.
Agathe was a part of the Bhoys side that went 77 games unbeaten at Celtic Park between 2001 and 2004.
Joel Agathe - son of former Celtic star Didier - has joined the Bhoys on trial.