LONDON (REUTERS) - Nico Rosberg may not have lost the plot, as some suggested in the wake of his outburst against Mercedes team mate Lewis Hamilton at last Sunday's Chinese Grand Prix, but he is feeling the heat.
The German's accusation that the world champion had been selfishly slow as he cruised to a pole-to-flag victory in Shanghai spoke more of mounting frustration than any real grievance.
Hamilton has won eight of the last 10 races and Rosberg, last year's runner-up in a title battle that went down to the wire, has won just once in that period and also been unable to assert himself in qualifying either this year.
Niki Lauda, the Austrian who won three titles and is now non-executive chairman of the Mercedes team, put it typically bluntly on Sunday.
He said: "Everyone drives selfish. What do you think these guys are here to do? I call them egocentric b*****ds. That is the only way to win and the only way to win the championship."
With Ferrari looking far more competitive, and Sebastian Vettel second in the championship after winning in Malaysia, Rosberg is facing pressure from more than just his team mate.
"Nico is just shooting himself in the foot by showing the world he's upset, as if the world can do something about it," commented 1996 world champion Damon Hill. "We can't do anything about it."
Added the Briton: "Nico has to outqualify Lewis, he has to take the fight and take the high ground and then maybe he's got a case to argue."
Hamilton, who set the fastest lap of the race, made the perfectly valid point that "it's not my job to look after Nico's race" and that he needed to make his tyres last.
He would not be the first driver to dictate the pace to suit himself - compatriot and triple champion Jackie Stewart was a master at winning at the slowest possible speed. Such tactics are part of every great driver's armoury.
Martin Brundle, the Sky television commentator who competed in 158 races and was team mate to Michael Schumacher in 1992, had no doubts who was in the right.
"Lewis is leading the race. I think he's entitled to do what he likes. If you want to change that, get in front of him. He was just controlling the race... he's got the high ground, he's got track position."
In the end, Hamilton was faster in practice, qualifying and the race. The mental cracks may be starting to show for Rosberg and the next race in Bahrain saw fireworks last year as Hamilton won a wheel-to-wheel duel between the two. Rosberg knows he needs to step up in Sakhir later this week.
"The worst part of the weekend was losing out to Lewis in qualifying, that compromised me the most," he said.
"It's all down to me to be five-hundredths quicker next time."