Lewis Hamilton led a Mercedes 1-2 at the top of the timesheet in the opening practice session ahead of the Formula 1 season-opening Australian Grand Prix.
Reigning champions Mercedes exchanged fastest times with Red Bull’s Daniel Ricciardo and Max Verstappen during the first 40 minutes of the session.
Hamilton gradually improved his pace, eventually setting the session best time of 1m24.026s. Bottas’ personal best, which was also set on the ultrasoft tyre, was 0.551 seconds adrift of his team-mate.
Mercedes similarly locked out the top of the timesheet in the same session last season.
Verstappen was third fastest, 0.771s behind Hamilton. The Dutchman set his best time on the supersoft tyre. Team-mate Ricciardo was sixth on the same compound.
Ferrari ran an alternative programme during the session. Kimi Raikkonen finished fourth despite being one of only two drivers to set his fastest time on the soft tyre – the hardest option available to the teams in Melbourne. Sebastian Vettel was fifth on the supersoft.
McLaren endured a return of the reliability issues which hampered its pre-season testing. Fernando Alonso suffered an exhaust issue early on. As a precaution, the team opted to keep team-mate Stoffel Vandoorne in the garage while the issue was resolved, limiting McLaren to a combined four laps after the first 40 minutes.
Eventually returning to the track with 20 minutes remaining, Alonso climbed to eighth on the timesheet while Vandoorne finished 10th albeit on the soft tyre.
Romain Grosjean filled the best-of-the-rest position for Haas in seventh. He was 1.3s clear of his team-mate Kevin Magnussen in 17th.
Carlos Sainz Jr was the leading Renault in ninth. Pierre Gasly impressed for Toro Rosso in 11th, Sergey Sirotkin finished 12th and Sainz’s team-mate Hulkenberg ended the session 13th.
The Sauber duo of Marcus Ericsson and Charles Leclerc finished bottom of the timesheet in 19th and 20th respectively.
