Sebastian Vettel led the field in Friday's rain-hit second practice session for the Hungarian Grand Prix.
Lewis Hamilton dominated the dry running at the Hungaroring on Friday morning, but the six-time world champion remained in his garage as poor weather disrupted the final action of the day.
Ferrari's Vettel finished two tenths clear of Mercedes driver Valtteri Bottas with just 13 of the 20 runners setting a competitive lap in the difficult conditions.
Carlos Sainz was third for McLaren, 1.3 seconds behind Vettel, with Racing Point's Lance Stroll fourth.
Hamilton is bidding to win the race in Hungary for an eighth time.
The 35-year-old is six points behind team-mate and championship leader Bottas in the drivers' standings.
First positive Covid-19 tests
Formula One has confirmed its first two positive Covid-19 results ahead of Sunday's Hungarian Grand Prix.
It is understood that the individuals were involved in setting up this week's race and are not employed by the 10 teams.
They have since been removed from the sport's bubble, with no impact on the third round of the championship at the Hungaroring expected.
"The FIA and Formula One can today confirm that between July 10 and July 16, 4,997 tests for COVID-19 have been performed on drivers, teams and personnel and of these, two people have tested positive," read a statement issued by the sport's governing body.
"The individuals were not present in Austria, with the affected people removed from operations and isolated.
"Tracing of close contacts has been completed and isolated. No specific details as to teams or individuals will be provided by the FIA or Formula One and results will be made public every seven days."
The sport is operating under strict Covid-19 rules to ensure the races can go ahead, with personnel being tested for the virus every four days.
The Hungarian government last week issued strict lockdown measures in a bid to prevent the spread of the disease.
All UK and non-EU members of the sport's 2,000-strong travelling circus are required to stay in their hotels when they are not at the track, which is situated 12 miles from the centre of Budapest.
The use of public transport and taxis have also been banned. Failure to adhere to the rules could result in a £13,000 fine or imprisonment. Seven of the sport's 10 teams are based in the UK.