Istanbul: Formula One champion Sebastian Vettel returned from his Friday crash to keep Michael Schumacher off the top of the timesheets by the slimmest of margins in final Turkish Grand Prix practice on Saturday.
The 23-year-old Red Bull driver pipped his illustrious Mercedes rival by just 0.001 of a second as clear blue skies and sunshine replaced the previous days' rain at the anti-clockwise Istanbul Park circuit.
Red Bull's Australian Mark Webber was third quickest behind the two Germans, followed by Schumacher's team mate Nico Rosberg.
McLaren's Jenson Button, who had been fastest on Friday while Vettel watched as a spectator after his heavy morning crash on the exit to a slippery turn eight, lapped fifth fastest ahead of team mate Lewis Hamilton.
Vettel, the championship leader after winning two of the first three races, will be gunning for his fifth pole position in a row in qualifying.
Red Bull have been on pole in Turkey for the past two seasons but have yet to win there, largely because their drivers collided last year while fighting for the lead in a race that ended in a McLaren one-two.
The form of seven-times world champion and former Ferrari ace Schumacher indicated Mercedes are catching up with Red Bull and McLaren.
Schumacher's fourth place in Turkey last year equalled his best result since the 42-year-old came out of three years of retirement last year.
Mercedes vice-president Norbert Haug said on Friday, however, that there was still plenty of ground to make up for the team.
"Potential winners? Not yet. We are working on it. I think that would be unrealistic," he told reporters.
"We are learning. It is getting better and better. We certainly underperformed in the first three races."
Ferrari's Fernando Alonso was eighth fastest, with Brazilian team mate Felipe Massa ninth.