Hamilton's best lap was -.0.127s faster than team-mnate Valtteri Bottas'. Picture: Lisi Niesner / Reuters

Spielberg, Austria - Formula One champion Lewis Hamilton led a Mercedes one-two in an overcast first practice session for the Austrian Grand Prix on Friday.

Hamilton, who has a 14 point lead over Ferrari's Sebastian Vettel after eight races, lapped the Red Bull Ring with a best time of 1m04.839s. Finnish team-mate Valtteri Bottas was second on the timesheets, 0.127s slower, with Red Bull's Max Verstappen the best of the rest at a circuit owned by Red Bull, 0.107 off Bottas's pace with Vettel fourth fastest in 1m05.180s.

Mercedes brought an aerodynamic upgrade to Austria, after a new engine was introduced at the previous race in France which Hamilton won, and looked again to be a step ahead of its rivals. The reigning champion has won every race at Spielberg since Austria returned to the calendar in 2014.

Pit crew work on Hamilton's Mercedes during the first free practice session. Picture: Ronald Zak / AP

Australian Daniel Ricciardo was fifth, ahead of Ferrari's Kimi Raikkonen and Frenchmen Romain Grosjean - who has yet to score a point this season - for Haas and Esteban Ocon in the Force India. Monegasque rookie Charles Leclerc, who has been impressive in the Sauber and is seen as a likely replacement for Raikkonen at Ferrari, continued his strong form with the ninth quickest time.

Honda-powered Toro Rosso had Pierre Gasly set the 10th quickest lap, and Robert Kubica made a Friday appearance for Williams, replacing race regular Sergey Sirotkin for the morning session only, but was the slowest man on track with a lap of 1m07.424.

McLaren had another lacklustre session, with Fernando Alonso and Stoffel Vandoorne 17th and 18th respectively although Alonso seemed to be mostly testing aerodynamic details. The former champion has said it knows it has an aerodynamic problem but cannot fix it in the wind tunnel, meaning it has to try out potential solutions on race weekends instead.

Results

1 Lewis Hamilton (Mercedes) - 1m04.839s

2 Valtteri Bottas (Mercedes) +0.127s

3 Max Verstappen (Red Bull) +0.233

4 Sebastian Vettel (Ferrari) +0.341

5 Daniel Ricciardo (Red Bull) +0.644

6 Kimi Raikkonen (Ferrari) +0.937

7 Romain Grosjean (Haas) +1.189

8 Esteban Ocon (Force India) +1.216

9 Charles Leclerc (Sauber) +1.376

10 Pierre Gasly (Toro Rosso) +1.555

11 Marcus Ericsson (Sauber) +1.561

12 Kevin Magnussen (Haas) +1.565

13 Carlos Sainz (Renault) +1.588

14 Sergio Perez (Force India) +1.616

15 Nico Hulkenberg (Renault) +1.640

16 Lance Stroll (Williams) +1.728

17 Fernando Alonso (McLaren) +1.773

18 Stoffel Vandoorne (McLaren) +1.859

19 Brendon Hartley (Toro Rosso) +2.032

20 Robert Kubica (Williams) +2.585