McLaren's Eric Boullier says Fernando Alonso is filled with rage, whether he's frustrated by defeat or enraptured in victory.
The Woking-based outfit's racing director admits another season of dismal performance with Honda saw the Spaniard boil over at times, referring to his post-race reaction in Singapore this year when Alonso punched a hole in the wall of McLaren's hospitality unit after he was taken out on the first lap of what he felt as a promising race.
"Sometime he has to express his frustration, but he has been like that in the past even winning races," Boullier told Motorsport.com.
"He is so tense after a race. It was the same [in Singapore].
"He has this rage inside him that he knows he can do better. He knows he can be the best. And he needs to show it. And I think if he wins, he will also punch a wall."
Boullier recently revealed that McLaren's doubts about Honda's revamped 2017 power unit materialised as soon as pre-season testing in Barcelona.
And the team's dashing hopes took their toll on Alonso who exited the winter raring to go and confident in a reversal of fortune by the Japanese manufacturer.
"As a competitor, he is making his mental preparation over the winter," explained Boullier.
"And he is drawing in his head how the season should be, and that even motivates him more because he tries to stick to his own goals.
"So turning up in Barcelona, and having been backwards in terms of engine performance, it is a mix of sadness, humiliation and frustration. It is not good."
McLaren convinced its star driver to remain on-board for 2018, thanks mainly to its new partnership with Renault.
The team will be under pressure to deliver a competitive package to Alonso however, and if it does, Boullier has no doubts the two-time world champion will keep his side of the bargain.
"I always compare him to a shark. When he can sense the blood, he goes straight there," said the Frenchman.
"And that is why if he feels he can be on the podium or competitive enough to be there, he will not give up one inch to anybody.
"So the pressure on the team will be there, but it is a good pressure."