The boss of a DTM team says it was "extremely fascinating" to get a close-up look at the working methods of Formula 1-dominator Max Verstappen.
Via his marketing company Verstappen.com, triple world champion Verstappen sponsors his friend Thierry Vermeulen in GT and DTM - the 21-year-old son of his manager Raymond.
And recently, Max joined Vermeulen at private tests in Portugal and Mugello with the team he chose for his young friend to race for - Emil Frey Racing.
It's a Swiss team named after former Sauber sponsor Emil Frey, a luxury car dealer. And it's headed by Lorenz Frey-Hilti, who explained to Blick newspaper what it was like to see Verstappen at the wheel of his DTM car.
It was a Ferrari 296 GT3, which Vermeulen races with the number 69. When asked to describe the experience of being in the inner sanctum with Verstappen as he tested the V6 twin-turbo, Frey-Hilti said: "It was extremely fascinating.
"Max is totally uncomplicated - a down-to-earth, nice guy without any airs and graces," he added. "After just one or two laps he's up to speed. He works extremely meticulously.
"You can feel how huge his passion for racing is."
Verstappen's test laptimes remain secret, but Frey-Hilti said of the session: "Max followed a clear test plan and makes very helpful statements to our engineers. It specifically helps us become faster, also because he adapts very well to what Thierry needs.
"Thierry is Max's friend, but he still wants to see performance. As a coach, he gives him strict and clear instructions."
Frey Hilti continued: "Max even convinced me to do a few laps myself." When asked if he came close to Verstappen's times, he laughed: "Not quite."
However, he said he has become friends with Max himself.
"There are countless GT3 teams," said the Emil Frey Racing team boss. "It was a great honour that he asked us.
"We didn't really know what was behind the request at the beginning, but I never would have imagined how intensively Max follows our races now."
