Vitaly Petrov has secured his first ever GP2 Series victory in the feature race finale at Valencia, the Russian heading Campos Grand Prix team-mate Giorgio Pantano for a breakthrough result for the team on home soil.

A surprise victory for a driver that came into the season as a relative unknown but comes out of it now as a race winner, Petrov triumphed in a typically exciting afternoon of racing that was blighted early on by a rain shower that deluged the Spanish circuit, although it was dry by its climax.

It was a resounding win too for Petrov, whose previous best result was a fifth place finish, getting a superb start in wet conditions to leap from eighth on the grid to third and inheriting the lead on lap seven, going from there to head home more illustrious team-mate Pantano by just over two seconds.

Indeed, the results reflected plenty of surprises - not least for the partisan Spanish fans - with many of the established front runners failing to make it to the chequered flag, creating the prospect of an exciting sprint race at least.

Most importantly for the title race though, Timo Glock was one of those that made the distance and has eked his advantage out to four points after finishing in seventh place, while Lucas di Grassi crashed out in the early stages. Although the Brazilian can still win the title, Glock will start the sprint race from second and needs to finish just fourth to guarantee that the title goes his way.

A downpour an hour before the race threw a curve ball into proceedings as the drivers got underway, the damp circuit always expected to dry before the end of the race, making strategy more important than usual. Nonetheless, those who chose slick tyres benefited most at the start, despite some damp patches, with a number of drivers flying off the line.

They included Petrov, who flew off the line, surging up from the fourth row to enter the first corner in third place, slotting in behind pole sitter Kazuki Nakajima and Roldan Rodriguez, the Brazilian showing impressive pace around the circuit on which he made his name whilst racing in Spanish Formula 3.

However, the Minardi Piquet Sports driver's charge was a false one when he took the lead of the race by the end of the first lap by finding a shortcut. Although it was the first time he has led outright all season, the novelty did not last long when he spun terminally just as a drive-through penalty was handed out.

Petrov was pushing though and, aided by a rather stubborn lapped driver Mikhail Aleshin who blocked Nakajima for much of the sixth lap, got the run on the Japanese driver and took the lead.

Indeed, Nakajima was beginning to struggle with overheating slick tyres, the DAMS driver working hard to keep Pantano in the second Campos car at bay but eventually succeeding the position to the Italian driver. The DAMS driver quickly came under pressure from countryman Kohei Hirate, but a wet kerb caught the Trident Racing driver out and sent him into retirement.

Circulating comfortably at the head of the field, Petrov took the conservative decision to pit for new slick tyres later than most of those willing to take a risk and came out back in the lead, holding a comfortable margin back to Pantano who was not quite able to make his extra laps on better rubber count.

Unusually, given his consistent form over the season, di Grassi has chosen a bad time to endure a disappointing race, the Brazilian shuffled into the mid-field and comfortably away from the top eight in the first few laps. As such, ART Grand Prix pulled a risky move in an attempt to get him back into play by switching to slick tyres on a still slippery surface on lap six.

A potentially genius move became one that has probably ended his title dreams after di Grassi could not handle the car on a tricky surface and duly spun away into the gravel trap. Leaving him at the back of the field for the second race, Glock and iSport are now champions elect.

Still, Glock himself was not having one of his finer drives, the German favouring a cautious approach on wet tyres, particularly given di Grassi was well behind him, and especially when he made a terrible start and slipped from second to sixth by the first corner.

Also misguidedly starting on wets, Luca Filippi was another to endure a race to forget, the Italian starting well but slipping gradually down the order with a problem before eventually spinning out of eighth place with only two laps remaining - thus surrendering pole position for the sprint race.

Together with Nicolas Lapierre (getting a bad start and being tagged by di Grassi), Adam Carroll and Bruno Senna (who had already been delayed by having to make two pit-tops before spinning) all failing to finish, the top eight took on a more varied look than usual - although it was clear what was making the difference around the tight, but sweeping Spanish circuit.

Indeed, Spanish drivers were in superb form, those that had driven the track in their Formula 3 days enjoying a definite advantage in tricky conditions that caught out those normally able to keep it on the straight and narrow.

As such, fourth place went, remarkably, to Marcos Martinez, the youngster enjoying a superb race in the Racing Engineering car after taking the risk of starting on slick tyres. Such was his pace, he was up to ninth place by the end of the first lap from 19th on the grid, fifth by the pit-stops before eventually crossing the line in fourth place, albeit well off the top three.

Behind him, Borja Garcia and Andy Soucek gave home fans yet more reason to cheer with fifth and sixth place finishes for Durango and DPR, the latter driver looking more confident than ever since his superb Spa-Francorchamps round. They even had the pleasure of overtaking a tentative Glock to record four and three points each, while Garcia's team-mate Karun Chandhok scored a useful extra point for fastest lap.

Rounding out the top eight was, rather unsurprisingly given how many times he has done so this year, Javier Villa, another Spaniard delighting the home fans. Starting from his fourth sprint race pole position of the season, having won the last three races he started from that place, who would bet against him making it a quartet in the final race of the season...?

That is for tomorrow though and for today it is Petrov and Campos that were the happiest people in the paddock. Together with Pantano second it marks a dream result for the team that are based just three miles down the road. Petrov's win also gives him the outstanding honour of being the first Russian to win an international single-seater race.

Pantano is just one point behind Filippi now in the fight for third place in the standings, although his team will have some repair work to do after Nakajima got too close to the Italian over the line and hit the back of his car.

Despite the rather inauspicious ending though, third place marks Nakajima's sixth podium of the season and although it was not the win he was likely hoping for, the Japanese driver will now end the season with best rookie status - no mean feat.

With some of the lesser positions decided now, attention turns back to the title race. However, with di Grassi starting down in 23rd and Glock will starting second, the title is very much in the grasp of the German and iSport International. It is one that is set to end ART Grand Prix's reign as the leading GP2 team, but as they say, anything can still happen.