Cyril Abiteboul has admitted that Renault messed up its start to the current 'power unit' era.

The French marque is still recovering, but now with its works team, a big step was made over the last winter period. Daniel Ricciardo is at the wheel in 2019 and a key focus is on improving the chassis, which is designed at Enstone.

Back in 2014, though, for the start of the current turbo V6 era, Renault only supplied engines. It had four clients: the two Red Bull teams, Lotus and Caterham.

Then, Frenchman Abiteboul was the boss at Caterham, having quit Renault to join the green-coloured Formula 1 team.

"At the start of 2014, one error followed another," he is quoted by the Dutch publication Formule 1.

"I was a Renault customer myself and I can tell you that they were really behind when it came to understanding the concept and the development of the engine," Abiteboul added.

He had left Renault in late 2012, sensing that the French marque was "going in the wrong direction" with development of the all-new V6 power unit.

"We did not invest enough or hire the right people in time. We were so fixated on the V8 engine that we simply forgot about the future. That was a big mistake," Abiteboul said.

After his Caterham adventure, Abiteboul returned to Renault where he took the helm of the then struggling engine supplier. By late 2015, Renault announced that it had bought Lotus and would operate as a works team for 2016 onwards.

It was by then that Red Bull's thorny relationship with Renault had started to foul completely.

"I understood their frustrations to a certain extent," Abiteboul says when asked about Red Bull.

"By then, Red Bull was used to success, but it ended for them," he added. "But criticising in the media doesn't solve anything at all.

"Eventually it reached a point where it was not only criticism of our product, but also of the Renault brand. For us, that went too far," said Abiteboul.