Ferrari's Sebastian Vettel topped the timesheets in final practice for the showcase Monaco Grand Prix with triple Formula One world champion Lewis Hamilton close behind for Mercedes.
Vettel, a four-times world champion, lapped the twisty street circuit in one minute 14.650 seconds - a mere 0.018 quicker than the Briton who was quickest in the first practice on Thursday (local time).
Mercedes's championship leader Nico Rosberg, winner for the past three years in the Mediterranean principality and chasing his fifth win in six races tomorrow, was third with a best time of 1:14.772.
Australian Daniel Ricciardo, fastest for Red Bull in Thursday's afternoon session, was fourth on the timesheets with Dutch team mate and Spanish Grand Prix winner Max Verstappen fifth despite clouting the barriers at Massenet.
The 18-year-old got back out on the track in the closing minutes after repairs.
After three practice sessions, the top three teams have all been fastest in one of them with every prospect of a close battle for pole later on Saturday.
Toro Rosso's Daniil Kvyat and Carlos Sainz were sixth and seventh fastest.
