Mercedes duo Lewis Hamilton and Nico Rosberg gave their explanations for the opening-lap crash that ended their respective races at the Spanish Grand Prix on Sunday.
Pole-sitter Hamilton was passed by Rosberg into the first corner, but the two-time defending Formula One world champion looked to hit back immediately.
An incorrect engine mode setting meant Rosberg was slow getting out of turn three, giving Hamilton the opportunity to close up behind his team-mate.
However, as Hamilton looked to move up the inside into turn four, Rosberg had moved across to close the gap, forcing the Brit onto the grass.
Hamilton lost control of his Mercedes and hit Rosberg from behind, seeing them both forced to retire from the race, handing Red Bull's Max Verstappen a historic race win.
Hamilton said he was "gutted" for the team but admitted he could have completed the overtake having seen a gap on the inside of Rosberg.
"Firstly, I want to make an apology to all of our team," Hamilton said. "When I stopped my heart just sank because there's 1300-odd people in our team who all work so hard for us to be here.
"To not deliver for them, it's honestly indescribable how gutted I was.
"I was catching him and he wasn't on the racing line, he was on the inside, slightly to the right [in turn three]. But the gap to the left was much smaller than the one to the right so I went for the right.
"There was a gap there and as a racing driver when you are going faster you go for the gap. I'm going to try to move forward, and to let the team know I'm going to do all I can to make sure it doesn't happen again."
Rosberg, however, admits he was "surprised" to have found his team-mate bearing down going into turn four in Catalunya.
"I had a great start and I was ecstatic after passing Lewis around the outside of turn one. At that point, it was my race to win," the German said.
"I came out of turn three and realised I was down on power with the wrong mode selected due to the engine mode switch being in the incorrect position.
"Lewis was closing in, so I decided to make a clear move to the right hand side as soon as possible, to close the door and show him that wasn't an option.
"I was very surprised that Lewis went for the inside anyway. The next thing I knew, we were in the gravel trap."
Rosberg now holds a 39-point gap over Ferrari's Kimi Raikkonen in the drivers' standings, with Hamilton a further two points behind.