Lewis Hamilton explained his side of the intra-Mercedes collision during the Spanish Grand Prix, and apologised to Mercedes for the squandered opportunity.
Hamilton and Rosberg diced for position on the opening lap and an incorrect engine setting through Turn 3 from Rosberg enabled Hamilton to get a run on his team-mate approaching Turn 4.
Hamilton adopted the inside line but Rosberg moved to the defensive, with Hamilton edged onto the grass in the process.
Hamilton spun out of control and collected Rosberg as the German attempted to round Turn 4, sending both into the gravel and retirement.
"I got a good start but I was slipstreamed into Turn 1, through Turn 3 I was quicker than Nico," he said.
"Nico happened to be in the wrong engine mode, I was gaining on him, I had decent pace, where he positioned the car there was a car width to the right of the racing line and I had to decide whether to go left, which is the racing line, or to the right.
"The inside line is always the one you go for, it's a much bigger gap so I went for it, I got there and I had part of my wheel and wing alongside within the white line but that diminished pretty quickly.
"I did what I could to avoid an incident but I was on the grass, and it all happened pretty quickly."
Hamilton apologised to Mercedes for the outcome but refused to be drawn on who was to blame.
"I’ve already apologised to the team, the most gutting thing when I stopped was thinking about the guys on the team giving me the opportunity to race, to not deliver for them," he said.
"I’ve been racing with them for a while now so not too often this happens but when it happens it’s painful for all of us but we’re united and we’ll come back strong."