Sochi FP1: Vettel sets the early pace

Vettel's best lap time of 1:34.488 was set on the Pirelli Hypersoft tyres, which was a mere half a tenth of a second faster than Max Verstappen in the Red Bull on similar rubber.

Championship leader Lewis Hamilton was third quickest, three tenths shy of the top time set by title rival Vettel, but the Mercedes driver used the slower Pirelli Softs as did his teammate Valtteri Bottas. The Finn ended the 90-minute session fourth fastest.

The difference between the Hypers and the Softs is expected to be around a second or so, depending on fuel loads and temperatures.

Daniel Ricciardo was fifth fastest in the other Red Bull, albeit nearly a second down on his Dutch teammate. The Australian's session cut short when his car caught fire in the pits.

Enjoying a good run was Esteban Ocon who was sixth fastest in the Force India, a tad quicker than Kimi Raikkonen seventh in the Ferrari, 1.2 seconds shy of his teammate.

Kevin Magnussen was eighth in the Haas, followed by Renault's Nico Hulkenberg in ninth and Sauber reserve Antonio Giovinazzi, on duty in place of Marcus Ericsson, ending tenth.

The Italian, who will drive for the Swiss team next year, was three tenths up on Ferrari bound Charles Leclerc in the sister car.

Other reserves in action included Artem Markelov, replacing Carlos Sainz in the Renault, who ended the session in 15th, albeit nearly a second down on Hulkenberg and Nicolas Latifi in action for Force India in 17th, 1.6 seconds adrift of Ocon.

Next year's McLaren rookie Lando Norris took over Fernando Alonso's cockpit for the morning, ending 13th and ahead of teammate Stoffel Vandoorne in 16th by nearly two-tenths of a second in only his second practice session in the car.