Lewis Hamilton topped the timesheets in both of Friday's free practice sessions for the Chinese Grand Prix.
But with a tenth of a second covering the top four at the end of the day, Hamilton is acutely aware that Mercedes can afford no mistakes this weekend in Shanghai.
"Ferrari were quick and Red Bull looked really fast on the long run," Hamilton said. "It's good to see all the times so close, but it means that we really need to bring our A game.
"We need everyone in the team to be on it throughout the weekend, because it is a joint effort."
Hamilton was certainly happy that Friday had gone to plan for the team.
"It has been a good day," he said. "We got through all the laps that we needed and got some good feedback about the car.
"The balance of the car is good, but we have some fine-tuning to do on it tonight," he continued.
"We've had a fairly normal Friday programme here," confirmed Mercedes' chief race engineer Andrew Shovlin. "Mainly we have been focussed on understanding the car balance and the tyre behaviour for qualifying and the race."
The day's preparations were complicated by changeable conditions. The afternoon session was effectively curtailed by 15 minutes by the arrival of light rain at Shanghai International Circuit.
"When I got to Shanghai the weather was really good," said Hamilton. "But it's gone downhill. Now we got the rain and it's cold." High winds had also been a factor.
According to Shovlin, the unsettled conditions are expected to continue on Saturday but improve in time for the race.
"The conditions are very cool today," he said. "Similar to winter testing.
"We are expecting more mixed weather tomorrow, and our normal qualifying preparation could be affected by a bit of rain in FP3.
"However, for Sunday the current forecasts show the sun coming out and we should get a much hotter track.
"Some of the work tonight needs to focus on that change of temperature for the race," Shovlin pointed out. "But even for the cool conditions we anticipate tomorrow, we have work to do on the balance to fine tune a few corners.
"It's clear that ourselves, Red Bull and Ferrari are closely matched on pace. And as always, they will be improving their cars overnight.
"We will be working with our usual diligence to try and find every last bit of performance."
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