Vettel left Red Bull - where he had come through the young driver program and became four-time world champion - at the end of 2014 to replace Fernando Alonso at Ferrari. Team principal Christian Horner said at the time of Vettel’s departure that he felt the German needed a new challenge, and Marko says he has already noticed a difference in the driver he helped nurture in to a world champion.
“He's in a good mood,” Marko told Bild. “He’s sending me naughty and funny text messages. Now he is back to the old Sebastian.”
Vettel topped the times on both of his days in the Ferrari SF15-T at the first pre-season test at Jerez, saying he was encouraged by the platform the team has to build from ahead of the 2015 season.
The second test takes place from February 19-22 and the final test from February 26-March 2, both at the Circuit de Catalunya in Barcelona.
Click here for the full gallery of the first photos of the SF15-T