McLaren driver Sergio Perez has admitted that his two crashes in practice for the Chinese Grand Prix have meant that he is not feeling confident with the car's handling.

Perez said that the reason for the second of his crashes, in FP2, is unknown, but he hopes to still make the third qualifying session on Saturday.

"It's been a very difficult day for me with the crash in FP1 and then I went off in FP2," Perez told ESPN. "We don't really understand what happened in FP2, it was a big moment and I don't understand what really happened.

"I was not pushing at that moment so I'm not very confident with the car and that makes things difficult. Tomorrow we will start from zero and I'm confident we can get into Q3."

Perez posted the 11th-fastest time in Friday's practice.