Jenson Button said he felt his McLaren team-mate Sergio Perez was the most dangerous driver on the track in Sunday's Bahrain Grand Prix.
After finishing 10th following an incident-packed race during which Perez drove aggressively and hit several of his rivals' cars, Button admitted he was disappointed with his Mexican team-mate.
Perez replaced Lewis Hamilton in the McLaren team this year after the Briton moved to Mercedes.
Button said: "I was very vocal on the radio, emotions were running high, but I would say exactly the same again.
"You don't expect your own team-mate to do that.
"The racing was great out there, except for one person - the only person who wasn't was 'Checo' (Perez).
"He was too aggressive, I would say. At 300kph, you don't expect your team-mate to come alongside you and bang wheels with you.
"It was a bit of a surprise, and I'm probably not the only one that feels like that."
The two McLaren men collided several times during the race as they battled for position, leaving team chief Martin Whitmarsh wincing on the pit wall.
One of the incidents left Perez with a damaged front wing as he clipped the rear of Button's car.
Button urged the team to make Perez "calm down" over the radio, but the battle continued and more contact followed.
But afterwards an uncompromising Perez said he felt Button had been equally aggressive.
"I think I was as aggressive as he was with me," said the Mexican. "It was probably too much. We could both have ended our races."
Perez finished sixth after his best performance for McLaren in four races so far, while Button had to make four pit stops and finished 10th.