Lewis Hamilton finished ahead of his Mercedes team-mate Valtteri Bottas by more than three-tenths of a second.
Ferrari-bound Carlos Sainz was fifth for McLaren ahead of an out-of-sorts six-time champion Lewis Hamilton in Mercedes.
Formula One returned with a bang in a belated, dramatic and incident-strewn 2020 season-opening Austrian Grand Prix.
Daniel Ricciardo will leave Renault for McLaren from where Carlos Sainz has been signed to replace four-time world champion Sebastian Vettel at Ferrari.
McLaren is a grand name in British racing that has produced cars featured in James Bond movies and bred winners of Formula 1 races since the 1960s.
Carlos Sainz emerged in pole position to succeed Sebastian Vettel at Maranello after the German announced Tuesday he was quitting Ferrari after talks over a new contract broke down.
Daniel Ricciardo will line up alongside Lando Norris at McLaren in 2021 after he leaves Renault at the end of this season.
The 2020 F1 world championship has been unable to start with eight races of a scheduled 22 already either scrapped or postponed.
The opening eight Grand Prixs of the 2020 season have been cancelled or postponed due to the COVID-19 pandemic.
The race was thrown into doubt on Thursday when McLaren pulled out after one of its team members tested positive for the virus and world champion Lewis Hamilton said he was stunned it was still going ahead.
McLaren withdrew from the season-opening Australian Grand Prix after a team member tested positive for coronavirus.
Fernando Alonso declined to give details and, when asked if he was talking to any teams about a comeback, smiled and said: "Always."
Lewis Hamilton approaches Thursday's Monaco Grand Prix opening practice in sombre mood, barely 48 hours after the death of Niki Lauda.
Fernando Alonso leaves Formula One with two titles, 32 race wins and boundless admirers for his talent.
Sainz, who in almost four years on the circuit has yet to feature on the podium, said he had been eyeing a seat at McLaren for a while.
McLaren were keen to keep the two-time World Champion in their ranks but he has now decided to leave F1 ahead of the 2019 campaign.
Red Bull will use Honda engines from the next Formula One season after agreeing an initial two-year deal.