RESULTS: Belgian Grand Prix - Free practice results (1)

Nico Rosberg has topped first free practice for the Belgian Grand Prix by a clear seven tenths of a second from Lewis Hamilton, as four teams trialled the Halo cockpit protection device and Fernando Alonso failed to complete a lap.

Taking place under sunny skies as the Spa-Francorchamps circuit bathes in a late August heatwave, Mercedes quickly picked up where they left off prior to the summer beak as both Rosberg and Hamilton sprung to the top of the timesheets.

Though Rosberg was using the Halo for a second run, he opted to take it to full speed on super-soft tyres and stop the clock at 1min 48.348s, which would remain the benchmark to the chequered flag.

EXCLUSIVE: Jenson Button - Why my F1 future is in my hands...

With Mercedes the only team to lap quickly on the super-softs, Rosberg was seven tenths quicker than Hamilton, the defending champion focused on set-up ahead of a race that will see him start towards the back following a raft of component changes. As it stands, Hamilton has notched up 15 positions worth of penalties, though this could grow further if Mercedes choose to take the opportunity to increase its pool of power units.

Kimi Raikkonen - a four-time winner at Spa - was third quickest, with Sergio Perez in the Force India splitting the Ferraris ahead of fifth place man Sebastian Vettel.

Main rivals Red Bull followed up in sixth and seventh, Daniel Ricciardo leading Max Verstappen on used soft tyres, with Nico Hulkenberg confirming Force India's pace in eighth. Valtteri Bottas was ninth fastest for Williams, albeit only using the medium tyre, while Esteban Gutierrez and Romain Grosjean followed in 10th and 11th despite both Haas drivers complaining about brake and grip issues throughout.

BACK TO FRONT: A history of F1 fight-backs!

Elsewhere, Alonso failed to complete a lap in the upgraded McLaren-Honda MP4-31 after suffering a water leak. Though McLaren insists the problem is not related to the update - which has been made possible after Honda used up seven of its tokens over the summer -, Alonso would sit out the entire session, while team-mate Jenson Button could only manage 18th quickest.

By contrast, Sauber enjoyed a strong session with its updated C35, Marcus Ericsson and Felipe Nasr a positive 13th and 15th fastest, while debutant Esteban Ocon raised eyebrows with the 16th best time, a full second faster than Manor team-mate Pascal Wehrlein and ahead of the Renaults he has been driving in FP1 this year.

As well as Mercedes, Force India, STR and Red Bull gave the Halo some additional mileage early on in the session, while most trialled Pirelli's new 'stronger' rubber as it looks to introduce the revised construction for later in the season.

Carlos Sainz, Nasr, Wehrlein and Kevin Magnussen all set their best laps on the soft configuration of the unmarked tyres.

BELGIAN GP: 6 Things to WATCH out for at the Belgian Grand Prix

Latest Tweets from & GPF1rst