Pierre Gasly has conceded Toro Rosso-Honda have "made a massive step back" in China and "lost all the strength" that was even present up until FP2 on Friday.
After being consistently in the top 10 all weekend in Bahrain and rounding off with a stunning P4 finish, the Frenchman came back down to Earth with a bump and was eliminated in Q1 in China.
"We knew top 10 would be difficult, but [we expected to be] around P11, P12, and actually to be a couple of tenths behind," Gasly said in the paddock.
"I think today we made a massive step back compared to yesterday, we lost a lot of performance, and that's what we didn't really expect.
"We made some changes and completely changed in terms of balance, it's completely opposite of yesterday, we lost all the strength of the car we had in the package, and [it's] just super tricky.
"I almost crashed in Turn 8 this morning, I almost crashed in Turn 10 as well. Just massive loss of rear grip.
"And yesterday [this] was actually our strength – good stability."
Gasly will line up from P17 for Sunday's race, with Brendon Hartley just two places up the road in P15.