Mercedes have admitted it has a tyre warm-up "concern" ahead of Saturday's qualifying sessions for the Monaco Grand Prix, despite its dominant day on Thursday.
The constructors' championship leaders topped both sessions on Thursday, with FP2 seeing Lewis Hamilton and Valtteri Bottas lock out the front row once again.
Mercedes have been in imperious form this season - recording five successive one-two finishes this season - and demonstrated its superiority once again in Monaco.
However, chief race engineer Andrew Shovlin has highlighted a cause for concern for Mercedes. Shovlin said that the W10 car was taking too long to get the tyres in the correct state for a flying lap, which could cause them some issues in qualifying on Saturday.
“We still seemed to have problems getting lap one out of the soft, despite the hotter track temperatures in the afternoon,” Shovlin said to Motorsport.com.
“Our number one concern is getting the soft tyre to work on the first lap; our headline times were good today but it took us a lot of laps to get there and qualifying is so important at this track.
“We've got Esteban [Ocon, reserve driver] in the simulator this evening and tomorrow so hopefully he can help with some of that learning.”