Charles Leclerc has revealed a forgetful mistake inside his Ferrari cockpit lay behind his power unit troubles in second practice at the Azerbaijan Grand Prix.
Ferrari has suffered a number of PU problems recently, with the most damaging in the Spanish Grand Prix when Leclerc was forced to retire from the lead.
Late in FP2 in Baku, the timesheet-topping Monégasque driver reported a loss of power over the team radio before making an alteration to the engine mode.
Asked if he was aware of what the problem had been, Leclerc conceded: "Actually, there were no power unit problems.
"It was just me that forgot that I had changed something which made me lose power but yeah, nothing weird."
Ferrari braced for hard Red Bull fight
Leclerc and Max Verstappen have gone wheel to wheel on a number of occasions this year and Azerbaijan looks set to again pit Ferrari against Red Bull.
Sergio Perez was second-fastest on Friday, with championship-leader Verstappen third.
Asked if he expects a hard fight on Sunday, Leclerc added: "I think it will be.
"We've had a good Friday because overall, I think we have improved quite a lot from FP1 to FP2 but there is still another step that we need to do from today to tomorrow.
"I also felt that in FP2, nobody really put a lap in and neither did we. Actually, I think Max and Carlos [Sainz] didn't actually improve on the softs so there are still quite a lot of question marks.
"The positive to take away is that the tyre degradation was good and the race pace was very strong so that is good."