Charles Leclerc burst onto the scene in 2018 with Sauber, earning himself a call-up to Ferrari for 2019 to race alongside Sebastian Vettel.
After a shaky start he would go on to seize that opportunity, scoring more wins, poles and points than his four-time World Champion team mate.
His on-track battles with fellow hot prospect Max Verstappen made for several entertaining and controversial moments throughout the 2019 season, and both are widely talked about as the ones most likely to take over from Lewis Hamilton at the pinnacle of F1.
Ecclestone isn't so sure though. He is good friends with Vettel and told him that he did a "s****y job" last season, but he doesn't see Leclerc as a future great.
Ecclestone told the Daily Mail: "He (Vettel) did a s****y job and I told him so. He finished where he deserved (fifth). Ferrari favoured Leclerc, 100%. They fall in love with a driver there (at Ferrari) and it is hard for the other guy. A lot of things went on against Sebastian.
"I think we have seen the best of Leclerc. He has done well and will continue to do so, but I don't think we'll see anything spectacular. The business in Canada upset Sebastian (when a penalty for squeezing Hamilton after running off track cost him the win]) He thought Ferrari should have backed him more and got stuck in. He's right."
Harder than expected
Current CEO of the F1 Group, Chase Carey, previously criticised the former regime under Ecclestone for complaining about problems rather than "fixing" them.
And Ecclestone said he believes that Liberty Media, who bought F1 in 2017, are finding out now that running the sport is harder than they thought.
Asked if he would ever be tempted to buy F1 back, Ecclestone said: "No. If the people at Liberty asked me to run the company I'd say no, 100%. It would be a case of trying to dismantle all the things they have put together.
"They have their own way of doing it. Chase had allegedly been Rupert Murdoch's right-hand man, which he wasn't, and they thought it would be easy, like a normal business. They have found out it isn't.
"For me, every deal is like buying and selling a used car. F1 needs a used car salesman."