Nico Rosberg said visibility problems cost him any chance of a good result at the Chinese Grand Prix, the German unable to see properly for most of the race.
"The main problem I had today was drops sticking to my visor which wouldn't run off making it virtually impossible to see," said the Williams driver.
"It's a problem related to my visor's anti-fog system which I've had in the past but haven't been able to resolve. 15 laps before the end of the race we were not in a good position so I asked to be switched onto intermediates as I thought we had to try something.
"For the first few laps, they were good. It looked like the way to go so I was quite pleased, but then unfortunately more rain came and it was all over again. Bahrain is only a week away and a good result, which everyone in the team deserves, is overdue."
Rosberg finished a disappointed 15th, having started from a promising seventh position.
Team-mate Kazuki Nakajima also had a day to forget after several mistakes. The Japanese driver retired from the race on lap 44.
"I had a transmission problem today so unfortunately I couldn't carry on with the race," he said. "It was very difficult out there with really poor visibility.
"There was a lot of standing water and it was hard to keep the car on the track, particularly on the exit of the last corner. I made some mistakes but it was the same for everybody."