Charles Leclerc says it was "a bit of a surprise" to see his Ferrari Formula 1 team lacking pace during Friday practice for the Japanese Grand Prix.
A resurgent Ferrari has won three of the four races since the end of the summer break, and Leclerc heads into the Japanese Grand Prix weekend on a streak of four pole positions, which he has recorded at both high- and low-downforce venues.
But despite a late improvement in FP2, Leclerc was only fourth at the end of Friday's Suzuka running, trailing the pacesetting Mercedes of Valtteri Bottas by 0.356 seconds.
"I think we made the most out of our day, which was the most important [thing], but it seems we are lacking pace this weekend, which is a bit of a surprise," said Leclerc.
"Because we were very strong in the last four races, we expected to be quite good here, but, yeah, it's less the case.
"The long run was not great compared to Mercedes. I think we were quite OK compared to Red Bull, more or less the same - I need to check the data, I haven't checked everything.
"On low fuel it seems that we are lacking a little bit of pace at the moment, so we need to work on that and to try to understand [why].
"The car didn't feel bad, the balance was quite good, but it seems that we are maybe lacking a little bit of overall grip."
Leclerc thought the competitive order in FP2 was "more or less the real picture of the weekend", after F1 declared those times would be used to set the grid should qualifying - already postponed to Sunday morning - be called off.
Asked whether Ferrari could make big strides in the absence of Saturday practice, Leclerc said: "It's going to be difficult, realistically.
"But I believe that I didn't drive very well today, so I need to work on driving first.
"Then we've got a few set-up changes to do on the car, and hopefully putting everything together we'll do a step forward."
Sebastian Vettel, who caught traffic on his final attempt in FP2 and wound up two tenths down on fellow Ferrari driver Leclerc, said Ferrari was "not as bad as maybe you think" but largely echoed his team-mate's view.
"I think we were quite OK, maybe just lacking a little bit of overall pace," he said.
"I think there was a bit of margin, it was not the perfect day for us so there's a bit more in the car - but you need to be honest, and Mercedes was very quick, every time they went out on track.
"Plus it looked a bit more comfortable for Red Bull as well here. So, it will be tight and I expect them both to be very strong on Sunday morning as well."