Sebastian Vettel has apologised to Red Bull team-mate Mark Webber for passing him against team orders to win the Malaysian Grand Prix.
The Red Bull drivers were told to hold station, with Webber ahead, after their final pit stops but Vettel ignored the call and overtook the Australian to win.
"I messed up. I would love to come up with a nice excuse or a nice story but I can't. That's the truth," Vettel said.
"I can completely understand Mark's frustration and the team not being happy."
Webber was clearly angered by Vettel's manoeuvre, gesticulating at his team-mate during the race and when they met for the first time after the race was over.
"After the last stop, the team told me the race was over," said Webber. "The team made their decision. Seb made his own decision and he will have protection as usual."
During the race, which Webber led from lap six, Vettel repeatedly asked the Red Bull management to make his team-mate move over for him.
"Mark is too slow," said Vettel at one point over the team radio. "Get him out of the way. He is too slow."
However, the team ignored his request and warned him to maintain a gap to Webber.
At one stage, when Vettel was trying to pass Webber after their final pit stops, team principal Christian Horner told the German to calm down, telling him he was being "silly".
But Vettel continued to attack and passed Webber around the outside at Turn Four with 13 laps to go.
Vettel appeared contrite after the race, admitting he owed Webber "an explanation" and claiming he had "misunderstood" the team's plans.
Asked if he was happy he had won, Vettel said: "No, I'm not. As I said, I did a mistake.
"If I could undo it, I would but I can't so it is not a great feeling right now and surely tonight is not going to be easy to fall asleep. I owe a proper explanation and apology to Mark and the team."
Webber was reluctant to say too much immediately after the race.
"It is still very raw at the moment because we had a plan before the race.... I should probably stop now," he said.
"It's very, very, very hard for Seb to sit there when we are told to bring the car home safely. I turned the engine down and was reassured twice that we would not use the cars against each other.
"It's very hard for people to understand the situation. They think they know what went on but they don't.
"Unfortunately, there is no rewind button but it will put some pressure on certain people. We have three weeks now before the next race and I will catch some waves on my board in Australia."
Red Bull motorsport chief Helmut Marko said the situation had "got out of control", while Horner said the drivers would need to resolve their differences.
"Drivers are drivers," said Horner. "We've seen it the other way around as well at races in the past between our two drivers. We will sit down and discuss it. Sebastian knows that it was wrong. He has apologised but we will sit down and discuss it."
Sunday's incident is the latest in a series of controversial incidents between the two drivers.
"They haven't been bosom buddies for a few years now," added Horner. "What Sebastian did today wasn't right. He acknowledged that. He has apologised. Hhe took things into his own hands."
Asked what Vettel meant when he said he had not passed Webber deliberately, Horner said: "He felt he hadn't heard the call. That it was unclear to him what the instruction was. But then again, we had the same thing in Brazil the other way around.
"He's obviously chosen to hear what he wants to hear. He's a race driver, he's competitive, he's hungry.
"He hasn't achieved the championships he has by not pushing the limits and he has pushed that today with his team-mate and the team."