Valtteri Bottas earned Williams the fastest lap time in the final practice before qualifying for the Austrian GP on Saturday, edging Lewis Hamilton’s Mercedes by 0.05 seconds.
Bottas completed the 4.3-kilometer Red Bull Ring in 1 minute, 9.848 seconds in the closing minute of the session to overtake then leader Hamilton.
Bottas’ teammate Felipe Massa timed 1:09.901 to give Williams a 1-3 finish.
It’s only the second time this Formula One season Mercedes has not been the fastest in the final practice.
“I am not totally suprised,” Williams deputy team boss Claire Williams said. “This track suites us with the long straights.”
Mercedes’ Nico Rosberg, who leads the drivers’ championship, posted the fifth time.
Mercedes team boss Toto Wolff admitted “Williams has been really fast.”
“The field has come together a bit more in general,” Wolff said after Hamilton and Rosberg clearly dominated practice on Friday.
Halfway through the session Saturday, Hamilton was only eighth and Rosberg 11th as Mercedes apparently was focussing on its long run pace instead of aiming for the fastest lap time.
Racing on its home circuit, Red Bull’s Daniel Ricciardo and four-time Champion Sebastian Vettel were more than half a second off the pace in seventh and 10th respectively.
Jenson Button, the 2009 Champion, had to quit the session after just four laps because of a problem with the rear brakes of his McLaren.
The qualifying for Sunday’s race starts 1200GMT. Mercedes has had pole position in all previous seven GPs this season.