The concern for Leclerc, however, is the rate at which the SF1000 eats through Pirelli's rubber.
"I'm extremely happy about today," said Leclerc. "P4! I didn't expect to be on P4 for tomorrow's race, and especially not starting with mediums, I mean we tried it, but we were not very confident about making it.
"To make it work was very nice and it is looking good for the race tomorrow because our race pace...we are struggling. I think we have the pace but we are destroying the tyres very quickly compared to the others so starting on the mediums will help us massively."
For Vettel, whose final lap time was deleted for exceeding track limits, it was another difficult day in which he encountered further pedal issues in FP3 after they had been replaced in FP2, while he also sat out first practice due to a minor problem with the intercooler system.
"I struggled to find the rhythm," said Vettel. "The car is not too bad but it didn't fit me today so struggling.
"Yesterday, obviously there were very little laps, and [again] this morning, to get into the rhythm. Nevertheless, I will try everything I can tomorrow and see what we can get.
"Looking ahead, starting on the soft tyre is not ideal, but it is what it is so we have to try and make the most of it."
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