Championship-leading teenager Kimi Antonelli bounced back to top the times for Mercedes ahead of both Ferraris in Saturday's final free practice ahead of qualifying at the Monaco Grand Prix.
The 19-year-old Italian, who had endured a torrid race last year and appeared off the pace in Friday's sessions, clocked a fastest lap in one minute and 12.720 seconds to outpace local hero Charles Leclerc by 0.327 seconds.
Seven-time champion Lewis Hamilton was third, just 0.004sec adrift of his Ferrari teammate, but unable to repeat his dominant speed from Friday when he finished fastest overall.
George Russell, in the second Mercedes, was fourth, seven-tenths off his teammate's pace, ahead of four-time champion Max Verstappen of Red Bull.
Oscar Piastri was sixth for McLaren ahead of Audi's Gabriel Bortoleto, Isack Hadjar's Red Bull and world champion Lando Norris in the second McLaren. Nico Hulkeberg was 10th in the second Audi.
The session, run in perfect dry conditions, was interrupted by a late red flag after Oliver Bearman crashed in his Haas on the run-up to Casino Square. He was unhurt.
Antonelli, winner of an unprecedented four consecutive races including his maiden win, is seeking to become the first Italian to win five races in succession since Alberto Ascari with Ferrari in 1952.
Hamilton, fastest on Friday, was the first man out as the session began in bright sunshine in the principality, his Ferrari glistening as much as his unique spangly pink helmet while close friend Kim Kardashian distracted photographers on entry to the paddock.
McLaren, the most successful team at Monaco and celebrating their 60th anniversary and 1000th race, had broken the overnight curfew regulations to make changes of various electrical items following Norris's problems in FP2.
The team were reprimanded and fined 20 000 euros ($23 000) for having taped over a clutch disengagement button, which had obstructed the marshals' bid to move the car, with a further 10 000 euros suspended.