Lewis Hamilton led a Mercedes 1-2 during an extended second practice session for Formula 1’s Canadian Grand Prix at Circuit Gilles Villeneuve.
The second session was extended to 90 minutes to partially compensate for the abandoned opening practice earlier on Friday afternoon.
A sync issue with the CCTV system, which caused a delay to the feed, meant the session could not take place after the opening few minutes.
The back-up system also failed and the time involved in addressing the failure meant first practice was unable to resume.
The repairs were completed between the sessions while an alternative back-up was put in place in the event of another failure.
Hamilton set a time of 1:13.718s to finish 0.027s clear of Mercedes team-mate George Russell, with the team carrying out its Soft tyre runs slightly later than their opponents.
Carlos Sainz finished third for Ferrari, 0.126s behind seven-time Canadian GP victor Hamilton, with Aston Martin’s Fernando Alonso fourth, ahead of Charles Leclerc.
Red Bull had an atypically subdued display, with Max Verstappen sixth and Sergio Perez eighth.
They were split by Alfa Romeo’s Valtteri Bottas, who notionally set the fastest time in the truncated opening session, while home representative Lance Stroll and Alpine’s Pierre Gasly rounded out the top 10.
The majority of the extended session took place in dry conditions as the threat of rain lingered before the weather system moved in during the final few minutes of running, deluging the hairpin.
There were two brief suspensions to the session as Haas and Alpine suffered setbacks.
The first red flag was caused when Nico Hulkenberg’s Haas VF-23 suffered an engine failure, with the German halting the car at the end of the pit straight.
The second came a few minutes later, when Esteban Ocon stopped his Alpine A523 at Turn 9 after a suspected loss of engine pressure.
Ocon’s stoppage marked Alpine’s second in as many sessions after Pierre Gasly encountered a driveshaft issue during the brief window of running earlier in the day.
Saturday’s final practice session for the Canadian Grand Prix is scheduled for 12:30 local time