Max Verstappen has conceded Red Bull has been left with "work to do" after finishing only sixth fastest during Friday practice for the Canadian Grand Prix.
On a bizarre day at the Circuit Gilles Villeneuve, FP2 was extended by 30 minutes following only five minutes of running in the first session as a CCTV synchronisation issue led to safety concerns for the FIA.
Verstappen and Red Bull decided to set its qualifying simulation times early in the second session at a time where the track surface was relatively green, meaning the sixth-place finish on the timesheets is rather skewed compared to the table-topping Mercedes times, which were set some 30 minutes later.
"It wasn't very straightforward with basically no running in FP1," said Verstappen, assessing his day.
"It was the same for everyone and at least we could get a bit of running in FP2.
"We still have a bit of work to do, the car is not fantastic over the bumps, over the kerbs - it is still not too bad but we definitely need to fine-tune a few things."
"A bit of a tricky session but sometimes, you have those days."
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Rain to throw up 'a few surprises'
Wet weather is set to hit the circuit on Saturday, with qualifying likely to take place under heavy rain.
Verstappen explained: "[Saturday] will be very wet and that normally brings a few surprises in qualifying, and we will see what the weather will do on Sunday."