Valtteri Bottas was left "puzzled" by Mercedes' "undriveable" W12 as Max Verstappen set the pace in both practice sessions at the season-opening Bahrain Grand Prix on Friday. (More Sports News)
Red Bull driver Verstappen topped the timesheets ahead of Mercedes' Bottas in FP1 and McLaren's Lando Norris in FP2 in Sakhir.
Seven-time Formula One world champion Lewis Hamilton was fourth and third respectively after team principal Toto Wolff said the best the Silver Arrows could hope for would be to match Red Bull's pace.
Bottas said of Mercedes' new car on the eve of qualifying for the first race of 2021: "The last long run we did was pretty inconsistent, and I couldn't really put any laps together, and the car, as I said, felt undriveable at times.
"A bit puzzled, but it's Friday and that's why we practice."
Dutchman Verstappen, who clocked a quickest lap of one minute, 30.847 seconds, knows Red Bull must build on an encouraging start when it really matters.
He said: "I was really happy but tomorrow is again a different day, even more windy, which with these cars is quite more tricky, so again we'll have to try and be on it, but again, a good start to the weekend,
"I was also really [happy] before, but of course, now we have to show what we can do in qualifying."
The drivers had to contend with a sandstorm in practice and face more testing conditions over the weekend, with high winds and temperatures of up to 38 degrees Celsius forecast.
Verstappen added: "Of course, with the heat, it's not easy to find a really good balance around the whole lap. I think it's a positive day.
"There are still things to look into what we can look better for tomorrow, but again, also tomorrow, I think it's going to be even more windy so that will be even more difficult to drive.
"That's the same for everyone, so we'll see what happens."
