Carlos Sainz says Formula 1 championship leader Kimi Antonelli needs to "calm down" after being branded an "idiot" by the Mercedes driver during Belgian Grand Prix practice.

Antonelli felt compromised by Sainz on the run out of Stavelot and rolled off the throttle before cutting in front of the Williams, while saying "Sainz, what an idiot!" over team radio.

For his part, Sainz said Antonelli "threw the car into me". He then got back ahead of Antonelli on the run down to Bus Stop, where it briefly looked like the pair might have another side-by-side encounter before Antonelli pulled into the pits instead.

Sainz was unimpressed with Antonelli's comment on the radio.

"I think he felt like I impeded him - I don't feel like I did," he said afterwards. 

"I guess nowadays with the SM [Straight Mode], if you don't get out of the way exactly like [the other driver wants]- you cannot turn because you have no downforce with the wings open.

"Maybe he felt like I could have got out of the way in a better way. 

"But I don't think he should call me an idiot either, on the radio, I think that's forbidden, to swear and insult a rival - so I think he should calm down a bit."

There was no investigation into the matter - and no specifically profane comment from Antonelli that would be expected to trigger some sort of inquest.

"I mean, he backed off out of a fast corner, you exit in seventh gear, and I had to abort and it was quite risky," Antonelli said afterwards. 

"So of course I was not happy with it and of course what I said probably, in the heat of the moment, is not the best - but it was quite dangerous."