Sebastian Vettel admits the revival of Ferrari's pace at the United States Grand Prix is welcome but also worrying based on how it came about.
The Scuderia tested a raft of upgrades on Friday though wouldn't run them for the rest of the weekend, however, they also reverted back to the package used before the Singapore GP when their slump was deemed to have started.
Also back was their top speed advantage down the straights and that allowed both Vettel and Kimi Raikkonen to challenge in qualifying with the latter going on to win the race.
“You can see it as good news but you can also see it as bad news," the German told ESPN.
“If we have to go back to a car that has been competitive three or four months ago, surely it can’t be good news if you think about it.”
What is also worrying Vettel is there is no apparent sign of what it was from the post-Singapore package that caused Ferrari's performance to drop.
“It’s a bit hard to explain. If you don’t see that there is a problem, you don’t think that there is a problem," he said.
“We felt the car was not as strong as it was before but if you don’t see there is anything wrong then you don’t know that there is something wrong.
“All the steps we did, they seemed to make sense but now, looking back, they didn’t. Clearly, there was something missed.
“We haven’t understood why and where the aero took off and started, there is a lot of stuff for us to do and understand, but I’m pretty sure we will do what is necessary and get on top of it.”
What didn't change though was Vettel's issues when going wheel-to-wheel as he again spun out of victory contention on the first lap after the slightest contact with Daniel Ricciardo.
“We had another recovery drive today, but I’m getting a bit tired of recovery drives," he admitted. "It’s fun to race but I’m pretty sure at that some point the coin might flip to the other side."
And then there's the championship, for what it's worth, with Lewis Hamilton needing just a seventh place this weekend to wrap up the title.
“They [title chances] are getting slimmer, but we will try to head to Mexico and get the best out of our car. Maybe there are some elements we can improve," Seb suggested.
“Probably the last four or five races, we haven’t done so well. Obviously, the last couple of months haven’t been good for us, in many regards."
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