Championship leader Sebastian Vettel maintained his impressive form by clocking the quickest time as Formula 1 returned to action in Monaco on Saturday morning.
Vettel set three laps rapid enough for top spot, his fastest a 1:12.395, improving on his benchmark from Thursday on the purple-banded Ultrasoft tyres around the Circuit de Monaco.
Vettel’s time was 0.345s faster than team-mate Kimi Räikkönen, the Finn completing a Ferrari 1-2 during the one-hour session.
Mercedes, having struggled in the second session, moved up the leaderboard, with Valtteri Bottas third, though Lewis Hamilton managed only fifth, the pair split by Red Bull’s Max Verstappen.
Daniel Ricciardo finished sixth in the session, the last driver to finish within a second of Vettel, but stopped at Sainte Devote after the chequered flag due to a brake-by-wire failure.
Toro Rosso continued its encouraging form with Carlos Sainz Jr. in seventh place, and Daniil Kvyat eighth, while Haas’ Kevin Magnussen finished the session in ninth.
McLaren remained in the thick of the midfield action, Stoffel Vandoorne 10th and Jenson Button 12th, but both head into qualifying facing grid penalties, after Button was forced to take on additional engine elements.
The changes mean that Button will take on a 15-place sanction, and is therefore highly likely to start his one-off race from the back of the grid.
Sergio Pérez split the McLaren drivers but Force India team-mate Esteban Ocon crashed out of the session at the second part of the Piscine complex.
Ocon turned in too early for the fast right-hander and clipped the barriers, the impact breaking his VJM10's suspension, sending him straight on into the outside wall as he attempted to negotiate the left-hander.
The Virtual Safety Car was implemented while Ocon's car was removed, the marshals having initially struggled to dislodge the wreckage from the Tecpro barriers.
Felipe Massa took 14th for Williams while Nico Hülkenberg placed 15th, as Renault’s struggles continued, following Thursday’s lack of pace.
Romain Grosjean finished almost a second down on Magnussen in the sister VF-17, followed by Lance Stroll and Jolyon Palmer, who also lagged behind their respective team-mates.
Sauber finished at the back of the pack, Pascal Wehrlein six-tenths clear of team-mate Marcus Ericsson.
