The two-time defending champion was never challenged on the Circuit de Barcelona-Catalunya after beating Carlos Sainz's Ferrari to the first turn.
Reserve driver Felipe Drugovich replaced Stroll as the teammate to Fernando Alonso in testing after the Canadian's accident while training in Spain.
Fernando Alonso showed his talent is not fading at the advanced age of 41, finishing third to give the Spanish driver a 99th career podium in his team debut.
The Aston Martin team in a press statement announced that Sebastian Vettel has tested positive for coronavirus.
Alonso was fastest in Friday’s second practice in his new Aston Martin ride, following up on the morning session when the 41-year-old Spaniard was second fastest.
