(CNN) -- World champion Jenson Button returned to form after his third lap retirement at the Monaco Grand Prix, by leading opening practice ahead of Sunday's Turkish Grand Prix at Istanbul Park.
Button, who is aiming for his third race victory of the season, clocked one minute 28.28 seconds beating the morning time of McLaren teammate and fellow-Briton Lewis Hamilton.
Hamilton could not repeat his time in the afternoon, finishing fourth quickest after the Red Bulls of Mark Webber and Sebastian Vettel -- who currently share the lead in the world drivers' championship.
"There is still more to come, which is always the case after a Friday," Button told the official Formula One Web site.
"I am happy with the car at the moment, even though there are always some things that you want to sort out," he added.
Ferrari's Fernando Alonso came home fifth fastest -- half-a-second off the pace -- while the Mercedes duo of Nico Rosberg and Michael Schumacher were sixth and seventh respectively, followed by the Renaults of Robert Kubica and Vitaly Petrov.
The second Ferrari of Felipe Massa, who won the race three times in a row from 2006 to 2008, completed the top 10.