After another relative under-performance in Malaysia, Valtteri Bottas says he needs to turn his fortunes around or "it won't be good for anyone".
The Mercedes driver came home fifth in Sunday's race, over thirty seconds adrift of team mate and second-placed man Lewis Hamilton.
The Finn was on the back foot at the outset in Sepang as he struggled with his car's balance on Friday and in qualifying.
Despite a string of positive results marked by seven podium in nine races, Bottas' outright performance with Mercedes has lingered, without a clear explanation for his decreasing pace.
"It's the most difficult time of my career," Bottas said.
"I just want to perform and I haven't been doing that for some time, for many varied reasons.
"There are many, many question marks on me given that in recent races Lewis has been going very strong and the gap between us has been growing.
"I definitely have to turn it around very quickly, if I keep doing races like this it won't be good for anyone."
Mercedes opted for identical settings for both its drivers although Bottas' W08 was fitted with a different - and new - aero package.
The Finn was on the offense as soon as the grid lights went off in Sepang but he efforts to keep up were vain as he conceded a spot to Red Bull's Daniel Ricciardo.
"Mechanically we made the car's set-up equal for both cars so the only difference was in the aerodynamics," he said.
"I was struggling more with the front end, which hadn't really been the case this year, in the mid-corner it's difficult to get the car to turn.