Ferrari emerged as a threat to Mercedes in the final practice session for the Monaco Grand Prix as Sebastian Vettel topped the timesheets by two tenths of a second.
Wet weather on Thursday meant that the hour session on Saturday morning was the first time the cars had run on super-soft tyres. Mercedes seized the opportunity immediately and both Nico Rosberg and Lewis Hamilton ventured out on long runs on the softer of the two compounds. To some extent that explains why the two Mercedes were slower than the Ferrari, but that should take nothing away from Vettel's lap, which was set on super-soft tyres that were also several laps old.
Vettel's quick lap adds to the excitement ahead of the all-important qualifying session on Saturday afternoon, with the two Mercedes drivers split by 0.35s and the true pace of both still unknown. Kimi Raikkonen could also be a contender but ended his session in the barriers after just 11 laps, giving his Ferrari team a repair job on the left-rear corner of his car ahead of qualifying. Raikkonen lost the rear midway through Sainte Devote and failed to gather it back together before clobbering the barrier. He came to a halt several metres later and the session was briefly stopped while the marshals cleared his car.
Max Verstappen also hit the barriers after losing the rear of his car at the final corner. He had been following a McLaren through the final sector and when it peeled off to the pits, his Toro Rosso swapped ends under acceleration. The crash damaged the rear wing but he was able to recover to the pits where the car remained for the rest of the session.
Meanwhile, his team-mate Carlos Sainz set the fifth fastest time as Toro Rosso again look capable of upsetting the senior Red Bull team, with Daniel Ricciardo just one tenth of a second faster in fourth place. Less than a second separated Ricciardo in fourth and Nico Hulkenberg in 13th, meaning a small mistake in Q2 could be the difference between a top ten grid slot and an early exit from qualifying. McLaren looks capable of getting among the top ten for the first time this year, with Jenson Button eighth fastest and 0.6s off Ricciardo.
Williams spent another session outside the top ten, but have a tendency to save their best laps for when it really matters in qualifying. Expect both Felipe Massa and Valtteri Bottas to feature further up the order in qualifying.