But when Gerhard Gribkowsky testified again on Tuesday, his latest tune was not as sweet for 83-year-old Ecclestone, who faces losing control of F1 and jail if ultimately found guilty.
Gribkowsky, then an employee for a state-controlled bank and therefore a public official, admitted what he was promised by Ecclestone influenced his behaviour.
"Of course I was aware at that moment that I mentally moved to a certain extent to the side of Mr Ecclestone," he told the court, according to Bloomberg.
"I grabbed the carrot. Afterwards, I didn't negotiate with the same toughness I had until then," added Gribkowsky, referring to the sale of BayernLB's commercial stake in F1.
Ecclestone's lawyer told the court he was "surprised" by Gribkowsky's apparent U-turn on Tuesday.
"We have to wait how many versions will still emerge and what we make of them," lawyer Norbert Scharf later told reporters.