Red Bull’s Max Verstappen was encouraged by his car’s performance in Friday’s second practice session but insisted that more progress would be required to challenge Mercedes on Sunday.

Verstappen clocked in third fastest in FP2, almost three tenths behind pace-setter Valtteri Bottas.

But the Dutchman nevertheless outpaced in the afternoon session Ferrari chargers Sebastian Vettel and Charles Leclerc, a performance that reflected the gains enjoyed by the RB15 after FP1.

    2019 Japanese Grand Prix Free Practice 2 – Results

“I think the first practice wasn’t so good, but the second practice we improved a lot. That seemed a bit more promising,” he said.

“Mercedes is very quick and we have some more work to do. But it was a decent recovery.”

Verstappen underlined the slight boost in performance delivered by Red Bull’s fuel partner Esso which has supplied a new mixture for Honda’s engine.

“The new Esso fuel also seems to be a good step forward in terms of power which is really positive,” he added.

“It’s only Friday so you can’t really tell where everyone is, but we were all pushing a little harder in FP2 in case qualifying doesn’t happen on Sunday and these times set our grid positions.”