Valentino Rossi explained why he blew up at Aleix Espargaro during second free practice for the San Marino Grand Prix on Friday.
Movistar Yahama rider Rossi was visibly infuriated after being forced to slow down during a flying lap due to Espargaro coasting on the racing line before entering the pit lane.
The pair continued to exchange hand signals and words while Espargaro cruised down the pits, with Rossi eventually putting the middle finger up at the Spaniard.
Rossi says it is not the first time he has had issues with the Suzuki rider, going on to explain why he became so heated.
"It happened exactly the same also in Austria," said Rossi, who sixth fastest at the end of FP2 in Misano, over half a second behind leader Pol Espargaro.
"I push and arrive behind the two Suzukis. Both riders see me: [Maverick] Vinales and Espargaro. Vinales go wide and Espargaro remain on the line. Sincerely I don't know why.
"After I say to him something. I say to him, 'what are you doing?' And he said to me, 'f*** you!' so for this I was angry.
"It's enough to say sorry. But they don't know the way to say sorry. It's better to say, 'f*** you!'"
Espargaro, meanwhile, said he received a visit from race director Mike Webb after the session, but continued to proclaim his innocence.
"He [Webb] came to the pits," the 27-year-old said. "It's not normal, because he never comes to the pits. He always calls you to go there. But I imagine, since it's Valentino, he came to the pits.
"He told me to be more aware, but I asked him if they checked the video, and he said 'Yes, and you are not in the middle, you did not disturb him'. And he said, 'But anyway, be more aware', and I said, 'I will not be more aware if I didn't disturb him'.
"I repeated three times to him, 'I disturbed him? Did you check the video?' And he told me no, I didn't disturb him. Then I say, 'Then go to talk with him, because I will not be more aware!'"