Friday's events in Germany are perhaps the most significant yet in the corruption scandal, as the man 83-year-old Ecclestone is alleged to have bribed to the tune of $44 million began his role as the prosecution's star witness.
Fascinatingly, prosecutors do not totally dispute Ecclestone's claim that Gribkowsky blackmailed him. According to the Guardian newspaper, the jailed former F1 banker on Friday even admitted he tried to "create pressure to reach an agreement".
On the face of it, Gribkowsky's testimony on Friday may have helped Ecclestone's case.
SID news agency quotes Gribkowsky as saying he and Ecclestone did not discuss "at any time" precisely what the millions in payments were for.
"I never asked the question," he added.