Lewis Hamilton believes he was ahead of Kamui Kobayashi when they made contact during the Belgian Grand Prix.
The McLaren driver overtook Kobayashi on lap 12 to claim fourth position, but the Sauber driver fought back and Hamilton blocked him on the inside. The end result was a crash into the barriers for the former World Champion as well as his second retirement of the season.
The 26-year-old Brit, who didn't know who he was battling with at the time, felt he had completed the pass when Kobayashi hit him.
"I'm not really quite sure [what happened] to be honest." he told the BBC Sport. "I just remember hitting in the wall - I hit the wall pretty hard.
"A bit unfortunate for the team - we were in a good position and as far as I was concerned I was ahead of whoever it was I was racing and then I just got hit by them and that was my race over.
"That's motor racing. There has been a lot of races where we haven't finished this year, so that's just another one of them."
McLaren struggled to match the Red Bulls and Ferraris during the early stages of the race, but Jenson Button - who started 13th on the grid - found some pace late on to claim a podium.
Hamilton believes he could have battled for a podium as well.
"I think we were struggling," he said. "For whatever reason we were massively slow on the straight, massively, massively slow and I guess that's really what got us in the position really.
"Everyone was just pulling away from me on the straights and I was only able to keep up on the infield. I think we probably had a little bit too much downforce on.
"Nonetheless we were in a good position still - we were still able to challenge and I got past one of the Ferraris. We maybe have been able to have at least got a podium."