Nico Hulkenberg branded Kevin Magnussen as "nasty" following an unsavoury row between the duo at the Hungarian Grand Prix.
Haas driver Magnussen was handed a five-second penalty for easing Renault's Hulkenberg off the track during Sunday's race, with the German subsequently forced to retire.
As Magnussen conducted a televised post-race interview, Hulkenberg approached and offered the Dane sarcastic congratulations for being "once again, the most unsporting driver of the grid".
Magnussen, who finished 13th, appeared to offer the somewhat offensive reply of "suck my b****s", and Hulkenberg was clearly unimpressed when he came to address the media.
"I congratulated him for being the most unsporting driver of the whole grid once again. When it comes to racing, he's just nasty," Autosport quoted Hulkenberg as telling NBC.
"Hard defending is fine but when he does this, it's just ruthless and sending people into the wall.
"What he did there, opening up the steering, making me run wide, it's just being an a******* basically.
"We had really nice words [a reference to Magnussen's post-race insult]... so it's quite interesting with him."