Max Verstappen was powered to victory in Mexico by anger.
That is the claim of his father Jos, who said the Red Bull driver was furious after missing out on pole despite otherwise dominating last weekend.
"I saw him on Sunday morning and he told me straight away that he had slept very badly," Jos, a former F1 driver, told the Dutch broadcaster Ziggo Sport.
"Max was annoyed about the car and missing the pole. But also by Ricciardo," he revealed.
"He (Daniel Ricciardo) celebrated his pole position with the exuberance of having become world champion. He (Max) was very angry and wanted only one thing: to win," Jos added.