Sebastian Vettel does not appear to be fully comfortable with life at Ferrari, according to former Scuderia driver Gerhard Berger.
Vettel returns to his home race at Hockenheim this weekend looking to atone for last year's DNF, which has sparked a downward spiral in performance.
A string of errors saw Vettel fall out of title contention last year and prevented him from entering it this campaign. He will begin Sunday's race 100 points behind standings leader Lewis Hamilton.
Berger is a key figure in Vettel's career – he was Toro Rosso co-owner when the German handed the team their sole victory to date in Monza in 2008 – and the Austrian says the unique surroundings of the Scuderia may be impacting his former charge.
"He has a hangover. Sebastian has never liked pressure. He has it at the moment, but he's coming out again," Berger told Speedweek.com.
"Sometimes it's inexplicable. There are duels, you find a rhythm, but it goes wrong the first time overtaking. But then it works well 10 times.
"And sometimes things go wrong right away. It looks funny from the outside and cannot be explained. But if you have the shit on the heels, that's just how it is."
Berger offered advice to Vettel: "Keep your nerves, just accelerate and try to show performance. And do not read a newspaper!
"Sebastian has to look where he feels comfortable.
"There are people who can deliver brilliant results, whether they feel well or not. And there are people who can only perform well if they feel good. Sebastian has to feel good.
"At Ferrari you can feel extremely comfortable, but there are also times when you feel extremely uncomfortable. Vettel is currently in the uncomfortable phase."
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