Championship leader Kimi Antonelli topped the times ahead of his Mercedes teammate George Russell in Friday’s opening free practice for the Austrian Grand Prix.
The two 'silver arrows' were out in front throughout the hour-long session, finishing more than a second clear of third-placed Oscar Piastri of McLaren, as they demonstrated complete supremacy.
The 19-year-old Antonelli, who leads the championship by 41 points ahead of seven-time champion Lewis Hamilton of Ferrari, clocked a best lap of one minute and 7.796 seconds to edge Russell by 0.040sec on a hot day in the Styrian Alps.
Four-time champion Max Verstappen was fourth for Red Bull, 0.281secs off the pace, ahead of Hamilton and Racing Bulls rookie Arvid Lindblad.
"It's a real struggle," said Hamilton, whose maiden Ferrari win in Spain had put him second in the title race.
Defending champion Lando Norris in the second McLaren, missed 45 minutes of the action due to hydraulics problems, and was seventh quickest.
The session began with six reserve drivers in the pack as Sergio Perez led the way in his heavily-updated Cadillac, one of several teams, including Audi, Red Bull, McLaren and Mercedes, introducing upgrade packages for the eighth round of the championship.
The race had been declared a heat-hazard event, enabling the use of cooling vests by the drivers, but the paddock chat was more concerned by various appeals following the Monaco Grand Prix, one of which saw Alpine's Pierre Gasly reinstated in third place.
He had been penalised for speeding in the pit lane, but the team proved that the speed limit had been miscalculated.