London: World champion Sebastian Vettel set the fastest time of the week as he gave a powerful display on the final day of F1 testing at Silverstone on Friday.
Red Bull star Vettel completed a total of 78 laps with a best time of one minute 32.894 seconds.
"We had three days of testing with a lot of different drivers in a lot of different cars and no failures -- in conditions that were hotter than the British Grand Prix -- so that's good," Vettel said.
"Obviously, we were very limited on what we could do, but for me there is not that much difference with the tyres.
"It was good to get in some laps though, good to get a feeling for them and it's always nice to drive at Silverstone."
Adrian Sutil had set the best time of the morning running for Force India, and he ended the day second-fastest, some three-tenths of a second slower than Vettel.
Nicolas Prost was third for Lotus with Carlos Sainz Jr fourth after another promising outing for Red Bull.
Development driver Susie Wolff did a solid job for Williams as she set the ninth-fastest time in her first full test for the team.
The 30-year-old Scot's only previous running for Williams was a familiarisation test at the tail-end of the 2012 season, and an aerodynamic test of the 2013 car in February.
"The team did a great job getting me through the day, talking me through everything step by step," Wolff said.
"In hindsight it would have been good to run the new tyres later in the day after I'd had more time in the car as I don't think I got the best out of the medium tyres.
"Physically it wasn't easy, but it was what I was expecting. I was well prepared so it was completely manageable. It was a fantastic experience."
The testing session was originally for young drivers but was expanded to championship stars to test Pirelli tyres.
Leading times on the third day of the Formula One young drivers test/tyre evaluation at Silverstone on Friday:
1. Sebastian Vettel (GER/Red Bull) 1:32.894 (79 laps), 2. Adrian Sutil (GER/Force India-Mercedes) 1:33.242 (99), 3. Nicolas Prost (FRA/Lotus-Renault) 1:33.256 (83), 4. Carlos Sainz Jr (ESP/Red Bull-Renault) 1:33.546 (35), 5. Davide Rigon (ITA/Ferrari) 1:33.592 (20), 6. Felipe Massa (BRA/Ferrari) 1:33.624 (69), 7. Jean-Eric Vergne (FRA/Toro Rosso-Ferrari) 1:33.647 (42), 8. Gary Paffett (GBR/McLaren-Mercedes) 1:34.294 (77), 9. Susie Wolff (GBR/Williams-Renault) 1:35.093 (89), 10. Giedo van der Garde (NED/Caterham-Renault) 1:35.155 (85), 11. Daniil Kvyat (RUS/Toro Rosso-Ferrari) 1:35.281 (22), 12. Charles Pic (FRA/Caterham-Renault) 1:35.576 (60), 13. Kimiya Sato (JPN/Sauber-Ferrari) 1:35.642 (67), 14. Rodolfo Gonzalez (VEN/Marussia-Cosworth) 1:36.339 (24), 15. James Calado (GBR/Force India-Mercedes) 1:36.451 (5), 16. Jules Bianchi (FRA/Marussia-Cosworth) 1:36.744 (39)