Red Bull advisor Helmut Marko admits he is a little worried about the apparent sandbagging by rival Ferrari, after Sebastian Vettel set a quick time on the penultimate test day, whilst obviously backing off as he exited the final corner.
Vettel's 1:19.024 was more than four-tenths quicker than anything by Red Bull – albeit slower than team-mate Kimi Raikkonen managed on the final day – but the German came off the throttle as he coasted over the finish line, suggesting there's much more pace in the SF17-H.
According to Marko, that suggests Vettel as "confidence" in the pace of Ferrari's car.
"Ferrari is very strong and reliable," Marko told ServusTV. "That's the difference to last year.
"What worries me somewhat is I know Vettel very well and he provocatively lifted on his fastest lap on the start and finish straight. Everybody could tell.
"And if you do something like this, then your self-confidence and knowledge about having a lot more in the car is huge."
Marko hinted that fuel loads and engine settings could be behind Ferrari's pace, with rivals keeping their cards close to their chest, but suggested the Italian team were the ones to beat at present.
"Nobody has shown their cards properly," he added. "If you're carrying 10kg more fuel, you gain about 0.35 seconds. Furthermore, engine mappings differ. This can gain you up to one second [a lap] – or it doesn't.
"A lot has been kept in the dark. But if the [first] race would have taken place with the same kind of temperatures we had then Ferrari would be in front, for sure."