Kimi Raikkonen set the pace heading into qualifying at the Spanish Grand Prix, leading a Ferrari 1-2 at the Circuit de Barcelona-Catalunya.
The 'Iceman' posted a 1m20.214s on the soft compound tyres in the final low fuel run, almost a quarter of a second faster than team-mate Sebastian Vettel.
The German's session ended on a sour note, however, as he stopped in the pit-lane heading out for another run with his mechanics now in a rush to complete a "precautionary" engine change ahead of qualifying.
After dominating Friday, Lewis Hamilton had to settle for third in final practice. He's looking strong compared to team-mate Valtteri Bottas, however, who missed much of the hour's running as Mercedes had to change back to the same engine that has completed the first four races following an issue with a fresh unit installed overnight. The Russian GP winner was able to complete a low fuel run at the end taking fourth.
One reason for the improvement by Ferrari could be a decision to dramatically reduce the minimum pressures set by tyre supplier Pirelli overnight after concerns over downforce levels went unfounded.
Behind, the two Red Bulls maintained fifth and sixth, with Max Verstappen again leading Daniel Ricciardo. The gap between them and the front did increase slightly compared to Friday to eight-tenths, but even if that was to be replicated in qualifying that would still mark some decent progress.
Nico Hulkenberg and Felipe Massa looks set for a battle to be best of the midfield, with the former Le Mans 24 Hours winner just ahead of the veteran Brazilian in seventh and eighth respectively.
Carlos Sainz moved up a place from Friday, finishing ninth for Toro Rosso, as fellow countryman Fernando Alonso gave the local fans hope in 10th for McLaren.
In the fight to make Q3, the two Haas' and two Force Indias were locked together with just over a tenth covering Grosjean, Magnussen, Perez and Ocon from P11 to P14.
Towards the back, Daniil Kvyat led the lead Sauber of Marcus Ericsson, with the second Williams of Lance Stroll also locked in a battle with a Renault, this time of Jolyon Palmer albeit in 17th and 18th.
After a strong Friday, Stoffel Vandoorne slipped down to 19th alongside Pascal Wehrlein on what would be the back row of the grid.
