Azerbaijan Grand Prix: Valtteri Bottas tops final practice for Mercedes in Baku

Mercedes' Valtteri Bottas led Ferrari's Kimi Raikkonen in final practice at the Azerbaijan Grand Prix as championship leader Sebastian Vettel hit trouble.

Bottas was 0.095 seconds quicker than his fellow Finn, with Vettel's title rival Lewis Hamilton third, 0.416secs down on his Mercedes team-mate.

Ferrari's Vettel managed just one quick lap because of a problem suspected to be a water leak and was 12th fastest.

The German leads Hamilton by 12 points after seven races.

The session was more encouraging for Hamilton, who had a difficult day on Friday, struggling with tyre temperature and traffic and failing to record a fully representative lap.

But the margin to Bottas will still be a concern for Hamilton, who has not looked at home throughout the weekend regardless of some of his issues being out of his control.

Some of Hamilton's deficit to Bottas may be accounted for by the fact that the Finn secured a slipstream from Red Bull's Max Verstappen on both his best laps.

Vettel's start to the session was delayed as the team investigated a problem. He was sent out after about 20 minutes and managed to record one lap before he was ordered to come back to the pits.

Verstappen was looking strong before his engine cut out about 10 minutes before the end of the session, and he ended up sixth. The team said they suspected a hydraulics problem.

Verstappen's team-mate Daniel Ricciardo ended up fourth, 0.545secs off the pace, with the impressive Esteban Ocon in the Force India fifth and just 0.057secs behind the Australian.

Williams's Felipe Massa was seventh, just two places and 0.302secs ahead of rookie team-mate Lance Stroll, whose confidence appears to have been transformed by scoring his first points with ninth place in his home race in Canada two weeks ago.

Stroll ended his session with a trip into the escape road at Turn Two after overshooting his braking.

The Williams drivers were split by the Toro Rosso of Daniil Kvyat, with Force India's Sergio Perez 10th.

McLaren's Fernando Alonso was 14th, but knows he will start from the back after a total of 40 places of grid penalties for using too many engine parts.

Renault's Jolyon Palmer had another difficult session. After crashing on Friday at Turn Eight, he pulled off early in the final session with flames and smoke pouring from the back of his car.