Valerio scores surprise Silverstone success.

His form in Turkey should perhaps have given a clue, but Alberto Valerio went from a 23-race also-ran to GP2 Series race winner in the space of three weeks when he triumphed in front of the British crowd at Silverstone.

The Brazilian paved the way for his success with a front row spot in qualifying on Friday, and made the most of it by producing a mature drive that combined enough aggression to pass poleman Romain Grosjean for the lead with a sensible pace thereafter to protect both his lead and his tyres. The Piquet GP driver duly led countryman Lucas di Grassi and Germany's Nico H?lkenberg to the flag.

A conservative start for Valerio meant that poleman - and pre-season favourite - Grosjean led the field, minus a stalled J?r?me d'Ambrosio, into Stowe for the first time, but a string of fast laps saw the Brazilian all over the rear wing of the Barwa Addax machine.

Showing considerable restraint compared to his old self, Valerio finally capitalised on all the pressure he brought to bear on the leader, sliding easily inside Grosjean at Abbey, before sailing off into the distance. The Frenchman was unable to respond as no sooner had he seen one Brazilian vanish from his mirrors, than another loomed in the shape of di Grassi.

The Racing Engineering ace had been the first to take advantage of a minor brush between Alvaro Parente and erstwhile points leader Vitaly Petrov at Copse, with the Russian running wide and allowing di Grassi, Javier Villa and H?lkenberg the chance to slot in behind the leading pair.

Two laps later, Grosjean lost another spot when he ran wide at Stowe, and then tried to squeeze di Grassi. Pushing too hard, he ran wide at Becketts next time around, slotting back just in front of H?lkenberg, who quickly decided to pit rather than lose any more time stuck behind the wayward Frenchman.

The move worked out for the German, who vaulted past everyone bar Valerio thanks to the timing of his stop, the Brazilian waiting until lap 15 to take on his madatory tyre change.

Sergio Perez had been the first man to make a stop, having started from the rear of the field after a qualifying nightmare. The Mexican pitted on lap seven, leaving the rest of the field to nervously eye each other to see who was going to blink first. The move worked for the Arden team, however, with Perez suddenly finding himself in contention.

There were battles up and down the field after the stops shook out, most notably with Karun Chandhok looking everywhere for a way past Grosjean, while Andreas Zuber sat behind them and waited to see what happened.

Valerio, meanwhile, looked was untouchable out in front, but the same could not be said for H?lkenberg, who was dropping back into the clutches of the pack, his tyres going away as a consequence of his early stop. Hampered by its worn tyres, di Grassi finally slipped by the ART car at Abbey, which forced Hulkenberg to slide across to cover the fast-charging Perez, up to fourth courtesy of his strategy, but seemingly not struggling in the same was as his quarry.

Try as he might, however, the former British F3 race winner could not find the gap he needed, but still deserved plaudits - along with his team - for rising from 25th on the grid.

When the flag finally dropped, however, it was another former British F3 protagonist - and a less successful one at that - who crossed the line punching the air with joy, Valerio claiming his maiden win ahead of di Grassi and Hulkenberg.

Grosjean was next up, in a subdued fifth place after holding off Chandhok for fifth, while Pastor Maldonado slipped inside Zuber on the final lap for seventh, although the UAE-based Austrian will now start Sunday's sprint from pole.

Championship-wise, Petrov's early misfortune meant that he was unable to defend his slim lead, allowing Addax team-mate Grosjean to reclaim the advantage by four points, with di Grassi moving up to third, a further nine adrift, level with H?lkenberg but five ahead of Maldonado. Valerio's win, allied to the five points he claimed in Turkey, moves him up to sixth place, one spot and two points behind d'Ambrosio.