Toto Wolff said he was surprised by how positive Lewis Hamilton still is despite Mercedes' awful season so far.
After five Grands Prix and a Sprint race in China, the seven-time F1 champion has just 19 points to show for his efforts. Every team remains in Red Bull's shadow, but Mercedes are significantly off the pace and are still struggling with a temperamental car which is difficult to get into the optimum performance window.
It is not how Hamilton would have wanted to spend his last season as a Mercedes driver. After 11 years, he is leaving at the end of the campaign to start a new chapter of his career with Ferrari, at the age of 40.
Particularly difficult for Hamilton will be the fact his future team is faring far better. Ferrari are a comfortable second in the constructors' championship and are only 40 points adrift of Red Bull, having taken full advantage of Max Verstappen's surprise DNF in Melbourne last month.
Hamilton has struggled when things have not gone his way in past years. But, speaking to Austria's Servus TV after Sunday's Chinese Grand Prix, Mercedes boss Wolff insisted his star driver remains positive.
He said: "Lewis is in a surprisingly good mood. I don't know if it's the knowledge that he will go somewhere else next year, but it's not like him at all - he's a true professional."
Hamilton has spent much of the season so far trialling different setups on his car in a bid to figure out how to unlock its potential. But, when he said that's what he had been doing after qualifying just 18th for the Shanghai race, his old team-mate Nico Rosberg slammed the Briton for making "excuses".
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The 2016 F1 champion, who was working as a Sky Sports pundit, said: "George [Russell] has mostly been in front of Lewis. 4-1 now, in qualifying. Lewis tends to say, 'Yeah but we have different set-ups and such a big car difference'. That is his excuse, so far this year. Each time he says that George says, 'The last time I checked, the cars are pretty similar'... He has gone again, for that."
Rosberg also described Hamilton's error in qualifying as "unnecessary" and a "disaster", and said it "should be avoidable" for a driver of his calibre. In response, the Briton insisted he was "very strong mentally" and said: "It wasn't one of my best qualifying laps.
"I don't blame anything on the team. It's not great, it's not a mind-f*** at all. S*** happens, you know? Sometimes you get it right, sometimes you get it wrong. This car is on a knife edge so it can easily do what we did."