BEIJING, May 26 -- Defending drivers' world champion Fernando Alonso laid down an early marker as he set the fastest time in opening free practice for Sunday's Monaco Grand Prix.

    The Spaniard, driving a Renault, clocked the fastest lap with a time of one minute and 16.712 seconds, just one tenth of a second quicker than Honda's third driver Briton Anthony Davidson.

    Alonso - who has never finished on the podium in Monte Carlo - set a time that was marginally quicker than his chief title rival, seven-times world champion Michael Schumacher of Ferrari, who wound up fourth.

    Alonso's Renault team-mate Italian Giancarlo Fisichella was third fastest.

    As is a tradition at Monte Carlo, the first practice sessions take place on Thursday - meaning times are often much slower as drivers lay down rubber on the barrier-lined street circuit.

    Most of the leading drivers left it late before setting a time in the morning session, giving their teams' third drivers a chance to shine and gain experience of the unique circuit in the Mediterranean principality.

    In addition to Anthony Davidson's time, Robert Kubica of Poland also impressed by claiming the sixth-fastest time for BMW, just behind former Monaco winner Juan Pablo Montoya of Colombia in a McLaren-Mercedes.

    Briton Jenson Button in a Honda was eighth-fastest while his compatriot David Coulthard, twice a winner in Monaco, was 11th quickest for Red Bull.