The Roman, third until his Michelin tyres gave up the ghost, said the 2005 event was his most difficult grand prix in nearly 150 race starts.
He said: "The car was really undriveable at the end. After Monaco, it is hard to be totally confident for a grand prix just one week later."
On a brighter note, the Nurburgring - although not the happiest hunting ground for Renault - should better suit the blue and yellow contender.
Giancarlo agrees: "For half the race (at Monaco), the car was among the quickest. I think we can come back strongly."