Ferrari's Sebastian Vettel beat Mercedes' Lewis Hamilton in final practice at the Monaco Grand Prix.
Vettel was 0.018 seconds quicker than Hamilton in a session that ended with few drivers showing their true speed.
Mercedes' Nico Rosberg was third, ahead of Red Bull's Daniel Ricciardo and Max Verstappen.
Dutch 18-year-old Verstappen was lucky to emerge with his car unscathed after hitting the barriers at the fast Massenet bend.
He ran wide at the 100mph corner at the top of the hill after misjudging his turn-in point. The Red Bull clouted the barriers but he was able to get back to the pits and get out again towards the end of the session.
Vettel did his final qualifying simulation run earlier than anyone else, while Hamilton looked on course to beat the Ferrari's time only to be held up by Toro Rosso's Daniil Kvyat in the Rascasse hairpin towards the end of the lap.
Rosberg was a further 0.108secs behind Hamilton - about the margin between the two Mercedes drivers in practice on Thursday, when they were out-paced by Ricciardo.
The unsatisfactory end to Saturday's session, a function of the cramped streets and too much traffic from too many cars out at the same time, meant there has been no read of the relative competitiveness of the top cars ahead of qualifying at 13:00 BST on a glorious sunny day in the Mediterranean principality.
And the final two minutes of the session were rendered useless when Renault's Kevin Magnussen ran wide at Sainte Devote, the first corner, bringing out the yellow caution flags.
Kvyat was sixth fastest just ahead of team-mate Carlos Sainz.
Force India's Sergio Perez was eighth, separated from team-mate Nico Hulkenberg by Ferrari's Kimi Raikkonen, who was 0.905secs slower than Vettel.
Williams' Felipe Massa was 11th, ahead of McLaren's Fernando Alonso, who did not manage a fast lap on the ultra-soft tyre and set his best time on the super-soft.
Nevertheless, the Spaniard was still 0.041secs quicker than team-mate Jenson Button, who did manage to do a time on the ultra-soft.
Renault's Jolyon Palmer was another to have a lucky escape. The Englishman lost the car in the 130mph Swimming Pool chicane and spun, but somehow only brushed the barriers with his rear wing.
Palmer ended up 20th fastest, a second slower than Magnussen, who like Ricciardo is running the new, upgraded Renault engine, worth about 0.2secs a lap around Monaco over the previous spec which is in Palmer's and Verstappen's cars.