NUERBURGRING (AFP) - Sebastian Vettel topped the times for Red Bull in Saturday morning's third and final free practice session ahead of Sunday's German Grand Prix.

The defending champion and current series leader, who has never won his home race, thrilled his fellow Germans with two fast laps in the closing minutes of the session to surge more than half a second clear of nearest rival and compatriot Nico Rosberg of Mercedes GP.

In front of a big crowd at the compact modern interpretation of the once-forbidding old circuit, the two Germans gave their home fans plenty to cheer ahead of Saturday afternoon's keenly-anticipated qualifying session.

But it was Vettel who delivered the best lap in 1min 29.517sec on soft tyres to crush his opponents' hopes before delivering a second lap of similar speed.

His team-mate Australian Mark Webber was third quickest in the second Red Bull ahead of two-time champion Spaniard Fernando Alonso of Ferrari - whose best lap was 1.1 seconds slower than that of Vettel.

Brazilian Felipe Massa was fifth in the second Ferrari ahead of Finn Kimi Raikkonen of Lotus, Briton Lewis Hamilton in the second Mercedes and Frenchman Romain Grosjean in the second Lotus.

Another German Nico Hulkenberg of Sauber rose to the challenge of his home event by clocking the ninth best time ahead of compatriot Adrian Sutil in the leading Force India.

Briton Jenson Button in the leading McLaren was 11th.

The Williams team's 600th Grand Prix suffered a setback early in the morning when Venezuelan Pastor Maldonado's car had a KERS failure in the garage. He was 17th ahead of his team-mate Finnish rookie Valtteri Bottas.