That left most of the field in unfamiliar conditions at the restart - just how much grip would the slicks allow on the still fairly damp circuit? Some could cope - Vietoris had no problems in front - while others struggled, with van der Garde missing the apex of turn 1 and sliding wide allowing Grosjean through before the Barwa Addax then clipped Bianchi's front wing as the Lotus ART man tried to follow the Dams car through. Bianchi and van der Garde continued their battle up into turn 4, with van der Garde following the racing line and sweeping across to the right and appeared to barge Bianchi off onto the wet grass, which predictably left him spinning into the run-off area at the top of the hill and dropping him to a miserable 22nd place.
But there were better fortunes elsewhere, particularly for Trident's Stefano Coletti. He had started on slicks from 21st on the grid and already knew their limits; taking the restart on lap 12 from 13th place, he blasted his way up to fourth in the space of a lap and a half, helped along the way by Razia and Bird getting preoccupied with a fight between themselves ahead of him. Pic also had crucial extra experience of the conditions and was able to improve to 7th as others fell away.
And then suddenly it was clear that something had changed: mayhem broke out up and down the running order. Filippi - not enjoying these conditions from the start - had spun again, and this time stalled the car; Julian Leal and Dani Clos also spun out; Pal Varhaug went out after clipping his front wing on the back of Davide Valsecchi's AirAsia car, which sent him ploughing through a gravel trap until he beached the Dams car half-in, half-out; and then crucially the leader Christian Vietoris lost control and spun out of turn 6, damaging his front wing and almost collecting Romain Grosjean, as the Frenchman was reacted fast to go off-track and avoid a more serious collision. That allowed Coletti to pass them both, assuming the lead.
It seems that what the teams had apparently not seen during the earlier safety car pit stops- or failed to take sufficient note of in the frenzied activity - was the rain radar saying that further rain of significant intensity was moving in to the area. It had now arrived, and the slick tyres that had always been a marginal call in the first place now had no chance whatsoever.
An escalating number of drivers including Lotus ART duo Jules Bianchi and Esteban Gutierrez had already decided to gamble on an early change back to wet tyres; some, including leaders Stefano Coletti and Romain Grosjean, stubbornly refused to surrender their track position despite slipping and sliding all over the place. But finally a safety car was called as a result of Clos' stalled car needing to be recovered.
It was another wholesale shake-up of the running order, and as the safety car pulled in it was now Charles Pic still on slicks in the lead followed by Coletti, Valsecchi, Grosjean, Kral, Sam Bird, Aleshin, Gutierrez, and van der Garde, with Kevin Mirocha in tenth ahead of Jules Bianchi whose timely pit stop decision had allowed him to recover to eleventh.
The cars on wet tyres were all able to take turn 1 much more coherently on the better grip, but those who weren't - including Pic, Valsecchi and Aleshin - all struggled and immediately lost started to lose positions hand over fist. The best gainers from all this were Gutierrez and van der Garde who quickly moved up to third and fourth behind the now-leading pair of Coletti and Grosjean. Gutierrez' team mate Bianchi had also done well out of the whole affair and was now in sixth behind Sam Bird, but even on wet tyres Bianchi was still struggling in the worsening conditions and ran wide while trying to overtake Bird, lucky to keep it going in the right direction and not spin again.
The wet weather and multiple safety cars had slowed down the race to the point where a time-cap was now inevitable reducing the race from 28 to 23 laps in length, and with just two minutes to go before the chequered flag was invoked there was another spinner in the form of Jolyon Palmer. Rather than bring out a safety car to recover the inconveniently-located stalled car, the officials chose to handle it under local waved yellows so that the race could finish under green.
And just as well, too, because there was a thrilling battle developing between Romain Grosjean and Esteban Gutierrez for second place. Grosjean seemed to be really struggling, which had released Coletti off into the distance in the lead, and Gutierrez clearly quicker - but the championship leader was doing everything that he needed do to impede the Mexican and keep him behind him on the track for one final lap.
It almost worked, until the very last corner of the last lap of the race: Grosjean finally slid too deep into the corner, and the better handling of the Lotus ART allowed Gutierrez to stick to a tighter line through the apex and get a better slingshot out of the corner and onto the start-finish straight. Gutierrez floored it and took the chequered flag by a tenth of a second from Grosjean.