Formula One world champion Max Verstappen topped the timesheets for Red Bull before taking a late spin at Albert Park in an eventful first free practice at the Australian Grand Prix on Friday.
The Dutchman lapped the lakeside circuit in one minute, 18.790 seconds, nearly half a second quicker than second fastest Lewis Hamilton of Mercedes, as two red flags disrupted the session.
Verstappen's team mate Sergio Perez was third quickest, with Aston Martin's Fernando Alonso fourth.
The session was halted midway through due to a GPS failure, which organisers said made teams unable to monitor car positions and closing speeds.
A second red flag cut the session short by a few minutes as Williams rookie Logan Sargeant came to a halt on track-side grass with an apparent power failure.
The first red flag led to plenty of traffic on the track and tempers flared as a number of drivers narrowly avoided ploughing into rivals.
Verstappen finished his session with a bit of drama, taking a big spin at turn four to ruin his tyres.
Ferrari drivers Charles Leclerc and Carlos Sainz were fifth and sixth quickest with McLaren's Lando Norris seventh.
Alpine's Pierre Gasly was eighth fastest ahead of Mercedes driver George Russell.
Hamilton complained of bouncing after a lap on medium tyres in a reminder of the team's 'porpoising' problems that plagued them throughout the 2022 season.
But he squeezed in a fast lap between the red flags to sandwich himself between Verstappen and Perez's times.
Home hero and McLaren rookie Oscar Piastri was 12th on the timesheet.
Haas's Kevin Magnussen, the slowest of the 20 cars, skidded into the gravel, while AlphaTauri may have some repairs to do after driver Yuki Tsunoda locked up at high speed to take a big slide through gravel midway through the session.