Carlos Sainz Jr can't explain big Japanese GP practice crash

Sainz ran wide out of the hairpin during the opening Suzuka session and speared back across the track into the barriers.

The impact caused a long red flag period, but Toro Rosso was able to get Sainz's car repaired in time for the final part of the wet second session.

"It was one of those accidents where you don't have an explanation," said Sainz.

"It was a mistake for sure from my side, and something I will obviously not like in the future to repeat.

"The mechanics fixed it in one and half, two hours.

"They did an amazing job and congratulations for that, it shows the commitment they have, and I really appreciate it."

Sainz already knows he is likely to start at the back having picked up a 20-place grid penalty for engine component changes.

"I knew a while ago, and I knew also my Saturday will be compromised because of that," he said.

"I will have to try and save some tyres for the race, to have the fastest race possible, so tomorrow is a not a normal day for me in that regard, working on long run preparation, working towards the race, because it doesn't matter where I qualify, I will start last.

"We haven't run a lot. P1 was tricky in terms of pace. We were pushing hard, but even if we were pushing hard, we were not very quick, so something to analyse for tomorrow, to see if we can find some pace.

"Anyway today it's very difficult to find conclusions."

Sainz added that Toro Rosso had long been considering making tactical engine element changes at Suzuka, before his failure in last weekend's Sepang race forced its hand anyway.

"We based it a bit on our last year's performance," he said.

"We knew that Suzuka was probably our weakest track.

"Anyway we were forced to do it because of the issue we had in Malaysia.

"We realised that we didn't have any more parts to put in the car.

"I'm pretty sure I will face some more penalties, unfortunately."