Sebastian Vettel and Ferrari set the early pace in a hot opening practice at the German Grand Prix.

As the top three teams employed different tyre strategies, the four-time world champion posted a 1m14.013s on the soft compound to finish a quarter of a second clear of teammate Charles Leclerc.

At Mercedes, they employed the alternative approach using the medium tyre in the second half of the session with Lewis Hamilton only 0.3s off the pace in third.

Max Verstappen would split the two Silver (and white) Arrows in fourth for Red Bull, setting his best time on the red-striped soft rubber.

In what is expected to be the final day of a record-breaking heatwave in Europe, temperatures were already through the roof at Hockenheim, forcing teams to take it easy in terms of performance.

The heat appeared to get to Kevin Magnussen's Haas as he ground to a halt approaching the Sachskurve, causing a red flag.

A sensor issue was quickly diagnosed, however, and the Dane was back out on track as the track went green again.

After that, the serious running began with Bottas and Hamilton separated by just 0.048s after the early runs on softs and Verstappen three-tenths back in fourth on mediums.

When the teams switched to the second set of tyres, the Briton found himself almost half a second clear of Bottas initially as both drivers ran wide in the final corner, kicking up the gravel.

The Finn would close by a tenth on his second lap but it was then the Ferrari drivers made their move.

First Leclerc moved fractionally ahead of Hamilton before Vettel then set the benchmark time on softs, which would hold until the end of the session.

There was drama in the closing minutes when Bottas ran off the track at the Sachskurve, narrowly avoiding the barrier, and Daniel Ricciardo spun on the kerb exiting Turn 1 but emerged unscathed.

Outside the top five, Pierre Gasly couldn't quite keep pace with the leaders as he sat eight-tenths down in sixth for Red Bull.

Carlos Sainz put McLaren at the head of the midfield in seventh, fractionally ahead of Romain Grosjean in eighth for Haas.

Lance Stroll offered encouragement for Racing Point in ninth, as the Canadian tested the first batch of upgrades expected over the next two weekends.

Finally, Ricciardo would complete the top 10 for Renault, despite his late spin.

As you'd expect at Hockenheim, the lap times were tight.

A second would cover the Australian in 10th to Robert Kubica in 19th, as the upgraded Williams showed some potential.

Indeed the Pole would be six-tenths clear of teammate George Russell, indicating the British team could make quite a considerable jump in performance.

Full results from Practice 1 can be seen below: