(AFP) - Valtteri Bottas topped the times for Mercedes in Saturday's (June 24) incident-filled, third and final free practice session ahead of Sunday's Azerbaijan Grand Prix.

The Finn clocked a fastest lap in 1min 42.742sec around the Baku street circuit on a hot day that saw all the usual suspects demonstrate they have the pace to claim pole position later on Saturday.

Bottas's time lifted him one-tenth of a second clear of nearest rival and compatriot Kimi Raikkonen of Ferrari as the two leading teams' second drivers led the way.

Three-time champion Lewis Hamilton was third fastest in the second Mercedes, showing an improvement on his struggles on Friday, ahead of Australian Daniel Ricciardo in his Red Bull, Frenchman Esteban Ocon of Force India and Dutchman Max Verstappen in the second Red Bull.

Championship leader and four-time champion Sebastian Vettel was 12th fastest for Ferrari, the German managing only seven laps in a session curtailed for him by hydraulics problems.

Verstappen's session also ended with him out of action after his car cut out and lost all power, leaving him to park it and abandon his challenge out on track.

Brazilian Felipe Massa narrowly avoided a crash into the wall in his Williams on his way to seventh place ahead of Russian Daniil Kvyat of Toro Rosso, Canadia Lance Stroll in the second Williams and Mexican Sergio Perez in the second Force India.

Stroll was one of many drivers who spun and recovered, but the most spectacular incident belonged to luckless Briton Jolyon Palmer whose Renault burst into flames after only six minutes.