Lewis Hamilton was at a loss to explain why Mercedes struggled so much in qualifying as the Brit settled for P4 on the grid for Chinese Grand Prix.
Although top in both practice sessions on Friday and setting the pace in Q2 amid a tyre bluff from Ferrari, Hamilton has struggled at the Shanghai circuit with various spins and a scruffy final lap in Q3 which forced him to abort it altogether.
He was out-qualified for as second straight race by team-mate Valtteri Bottas, too, and was half a second down on the pacy Ferraris that locked out the front row.
Mercedes boss Toto Wolff feels the car is suffering from tyre issues, but Hamilton does not believe there is a clear answer at this stage.
"The car felt OK but I don't really have the answer for it," Hamilton said.
"I think it's in the top three of the easier tracks to overtake. The Ferraris are too fast on the straight so it will be interesting.
"It's a lot hotter tomorrow so it will be a challenge to see if we can keep up with them.
"I don't know if we can challenge – we were half a second behind today. We were quicker in the last race but they were able to hold on and will probably do the same tomorrow."