Button sets pace in Istanbul
Reigning world champion Jenson Button attempted to put his Monaco pain behind him by finishing fastest in practice ahead of Sunday's Turkish Grand Prix.
McLaren team-mate Lewis Hamilton had led the way in the initial 90-minute session at the Istanbul Park before Button gave himself hope of a third win this season, and second in a row at this track.
Button set a time of one minute 28.280secs for the 5.338km track, a fraction quicker than last season's pole lap from Sebastian Vettel for Red Bull, and beating Hamilton's time by 0.4secs.
It is at least a step in the right direction for Button following his third-lap retirement in Monte Carlo due to an overheating engine caused by a foam bung mistakenly left in a sidepod covering the radiator.
Hamilton had to settle for fourth best in the afternoon run, only 0.019secs slower than his time in the morning, as the McLaren duo sandwiched the Red Bulls of Mark Webber and Vettel.
Webber has been the man of the moment of late, winning the last two races in Spain and Monaco at a canter to take over the lead in the championship standings for the first time in his career.
The 33-year-old Australian finished within 0.098secs of Button, but appeared to suffer an issue with his Renault engine in the closing moments.
Webber's Red Bull ground to a halt with wisps of smoke emerging from the engine cover, much to the consternation of team principal Christian Horner.
Behind the leading quartet, who appear certain to be the primary contenders for pole in tomorrow's qualifying, Ferrari's Fernando Alonso finished just under half a second off the pace in fifth.
