Sebastian Vettel topped the times for Red Bull in Saturday morning's third and final free practice session for this weekend's Belgian Grand Prix.
The defending triple Formula One world champion and 2013 title race leader clocked a best time of one minute and 48.327 seconds around the majestic seven-kilometre track in the Ardennes.
The 26-year-old German's best lap came in the final minutes of a one-hour session run in dry if overcast conditions and lifted him 0.105 seconds clear of nearest rival Spaniard Fernando Alonso of Ferrari.
Vettel's Red Bull teammate, retirement-bound Australian Mark Webber, was third fastest, 0.206 adrift of the German, but ahead of in-form Frenchman Jean-Eric Vergne of Toro Rosso and fifth-placed Brazilian Felipe Massa in the second Ferrari.
Briton Jenson Button was sixth for McLaren ahead of Mexican Esteban Gutierrez of Sauber, Frenchman Romain Grosjean of Lotus, German Nico Rosberg of Mercedes and Finn Kimi Raikkonen in the second Lotus.
Briton Lewis Hamilton, winner of last month's Hungarian Grand Prix, was down in 12th place in the second Mercedes and clearly struggling to recapture the form that brought him three consecutive pole positions.
The drivers took part after overnight investigations by Pirelli found the piece of metal debris that caused two high-speed punctures during Friday's practice sessions.
Following a detailed examination of the circuit between turns 13 (Fagnes) and 15 (Stavelot) where the incidents occurred, Pirelli discovered that a metal skidplate was the cause of the punctures and that it was not a tyre-related issue.
"No issues from our perspective," Pirelli motorsport director Paul Hembery said. "We've seen no signs of fatigue. From our point of view, there is no reason to be concerned."
