MotoGP champion Marc Marquez says he does not know why he crashed out of the lead of the Argentinian Grand Prix.
The Honda rider did not waste pole position and skipped away to lead by 2.248 seconds after three laps.
REPORT: Vinales wins crash-laden Argentina MotoGP race
However Marquez then lost the front of his Honda braking at Turn 2 and crashed out of the race, with team-mate Dani Pedrosa having an almost identical accident 10 laps later.
While Pedrosa explained he "lost the front over the bumps", Marquez was in the dark about what prompted his fall.
"Honestly, I don't know," he said.
"The crash was really strange. I was just at 25 degrees lean angle.
"I was completely straight on that brake point, OK I locked the front and for some reason it was not ready enough, the tyre.
"I was feeling really good with the bike. I was pushing but not a lot.
"It was just my mistake. Of course I'm really disappointed with me, because I know that these kind of mistakes can impact a lot on the championship, but now it's already done."
Marquez said he was surprised by his early lead, feeling he was "not extremely fast" but had simply settled into the race pace earlier than his pursuers.
"After three or four laps the others also got into 1m39.8s, 1m39s-high, 1m40s-low," he said.
"That was the rhythm of the race, for that reason I was leading the race.
"I was leading two seconds and the people can think 'he was pushing too much', but I wasn't pushing a lot."
MARQUEZ 'PUSHED LIKE AN ANIMAL'
All five Honda riders opted to use the hard front tyre in the race, amid 11 all up, with LCR satellite rider Cal Crutchlow finishing third.
Crutchlow was second to Marquez initially before being passed by eventual victor Maverick Vinales, and said he was content to let his stablemate run his own race.
"If somebody crashes, you always wonder why they crashed," he said.
"I'm sure I understand why he crashed, because he pushed like an animal at the start.
"I was happy to let him go, same as when in 2015 here I also let him go in the first lap and he was already on the limit on the first corner, nearly had a highside going in.
"So I let him go, and said 'OK, keep the other guys behind me for a lap or so and then try to come across to Marc'.
"Normally he's able to push and then you are able to catch him, but he made a mistake, unfortunately for him.
"We know the bike is critical in this area, we all ran this hard-spec front tyre and two of the guys crashed and I managed to stay on the bike."