Valtteri Bottas showed Mercedes' hand in final practice for the Azerbaijan Grand Prix as he topped the timesheets ahead of fellow Finn Kimi Raikkonen.
After Red Bull's domination on Friday, it looked to be business as usual at the front with both Mercedes and Raikkonen's Ferrari in the top three. Bottas remained at the summit of the timesheets for the majority of the session, setting an impressive time initially on the yellow-marked soft tyres which was beaten by nearly a second when he switched onto the super-soft -- finishing on a 1:42.742.
Lewis Hamilton was not as comfortable as teammate Bottas and was 0.416s slower. Fellow Formula One title rival Sebastian Vettel was only 12th fastest and did not partake in the final 25 minutes of running after a hydraulic issue, but Ferrari expects Vettel's car to be ready for this afternoon's qualifying session.
Daniel Ricciardo ended the session fourth fastest, but Red Bull's true pace was masked after Max Verstappen suffered a suspected hydraulic leak late on when he was on his fastest lap of the session. The Dutchman stopped at Turn 17 with ten minutes on the clock and eventually ended the session in sixth place behind Force India's Esteban Ocon.
Both Williams drivers will be fancying their chances of making Q3, with Felipe Massa and Lance Stroll in seventh and ninth place respectively. Sergio Perez rounded out the top ten but was 0.8s off teammate Ocon.
Nico Hulkenberg was just outside the top ten in 11th in an uneventful session for the German. Carlos Sainz was 13th ahead of Fernando Alonso. Both Haas drivers continued to struggle under braking and were often found down the escape road.
Kevin Magnussen was 15th, 0.2s clear of Stoffel Vandoorne in 16th who in turn was ahead of the second Haas of Romain Grosjean and the two Saubers.
Jolyon Palmer's torrid weekend continued as he suffered what looked like a power unit failure, which resulted in flames coming out of the back of his Renault. After crashing at Turn 8 in FP2, Palmer has completed just a handful of laps and is under immense pressure to perform going into qualifying.