Whatever happened to that nice, well-behaved, somewhat quiet and shy Valencia street circuit? The one that everyone dismissed as being rather dull for racing on? It certainly wasn't in residence this weekend for the GP2 Series, with the incident-packed Saturday feature race now followed by a sprint race that began with more of the same but ended up delivering an edge-of-the-seat thriller in the final laps.

Lotus GP's James Calado had been promoted to pole position for the second time of the weekend, after Davide Valsecchi had been penalised following the feature race and lost his spot on the reverse grid. That gave the Briton the chance to make amends for his Saturday disappointment, and he set to work with another perfect start off the grid that promised good things to come.

It wasn't the best flyer on offer: even better starts further down the grid were on display from Caterham's Giedo van der Garde, iSport's Marcus Ericsson and Calado's own Lotus team mate Esteban Guti?rrez. Van der Garde navigated a relatively safe path down the middle of the track, while Ericsson tried to sweep around the outside of turns 1 and 2 followed by Guti?rrez.

That put Ericsson wheel-to-wheel with the Racing Engineering car of Nathana?l Berthon who had beaten a sluggish Max Chilton off the line for second place; Berthon had his own problems on the inside with Chilton's Carlin team mate Rio Haryanto forcing his way through, and the three-wide mix into turn 2 didn't leave enough room on the outside for Ericsson to clear the barrier. He went into it and came to a crunching halt.

Following immediately behind the iSport and with his own wheel-to-wheel battle going on with Racing Engineering's Fabio Leimer, Guti?rrez had no warning of his forthcoming emergency stop; similarly, the Coloni of Stefano Coletti planted itself in the back of the Lotus, and then the DAMS of Davide Valsecchi thumped into the back of the Coloni in turn. The safety car was called to allow for the four cars to be disengaged, of which only Valsecchi was in any state to resume the race. Ericsson, Coletti and Guti?rrez all returned to pit lane to watch the race from the sidelines, joining Venezuela Lazarus GP's Fabrizio Crestani who had been unable to take up his grid position because of the damage sustained to his car in his somersault accident on Saturday.

The race resumed on lap 4, and immediately there was another accident requiring a safety car. Johnny Cecotto Jr. had run slightly wide out of the final corner and briefly run wide, and when he moved back onto the main straight it was into contact with Jolyon Palmer who hadn't left enough room for Cecotto to recover. The Barwa Addax car was left in the middle of the straight broadside-on, and Palmer's iSport was comprehensively trashed in the turn 1 runoff.

Calado faced yet another trial-by-restart on lap 6, and yet again proved up to the task by maintaining the lead of the race ahead of the Carlins of Haryanto and Chilton, followed by Leimer and van der Garde. But the latest restart was not without incident, with sixth-placed Berthon treading all over the front wing of Fabio Onidi's Colini and Caterham's Rodolfo Gonzalez encouraging Stephane Richelmi into a race-ending head-on nudge against the barrier.

Fortunately both incidents were quickly cleared up by the track workers without recourse to yet another safety car. The person to gain the most from the restart incidents had been Luiz Razia, who had been behind Berthon and Onidi's scrap and used the opportunity to muscle his Arden car cleanly past Berthon for sixth place. With that done, the race finally started to find its rhythm and everyone settled down to some proper green flag racing.

It seemed obvious that Calado would now repeat his Saturday march away from the field to draw out a big lead - but that didn't happen. Haryanto stayed with him, and if anything the Carlin was looking far smoother and more settled than the leading Lotus during the first half of the race. Gradually it became clear that Calado was starting to struggle, in particular repeatedly locking up into the final corner that led onto the main start/finish straight. Haryanto waited, and watched.

Haryanto's best chance came at the end of lap 14 when Calado ran wide through the corner, and Haryanto beat him across the line; but Calado hung in and maintained the inside line, finally forcing Haryanto to concede the position back to him a few corners later. However, the writing was on the wall and while Haryanto settled back into second to bide his time, no one was under any illusions that the Haryanto considered the matter closed. In the meantime, the attention turned to the battle for third place between Chilton and van der Garde which was hotting up as the end of the race approached, while van der Garde watched on from behind in case their antics allowed him an opportunity of his own to capitalise. The leading five were up to six seconds ahead of Razia, who seemed well and truly out of consideration.

Then on lap 20, everything changed: Haryanto had done enough waiting, and tried springing an attack on Calado into the turn 12 chicane. It didn't work, and Haryanto slithered into a collision with the side of the Lotus that tore off his own front wing. It left the Carlin fatally crippled and ultimately parked against the barrier, and Haryanto with a five-place penalty for Silverstone for causing an avoidable collision. Calado was somehow able to continue in the lead, as behind him at the same time Leimer was too preoccupied taking what was now second place from Chilton to even think about the lead at that point.

Whether because of collision damage or tyre wear, the Lotus was clearly no longer the car is had been: it was almost painfully slow, Calado only managing to maintain his position over Leimer by taking the most flamboyant sweeping turns through the corner to stop the Racing Engineering car from getting past without actually technically blocking him. But the way that Leimer, Chilton and van der Garde soon packed up behind Calado's rear wing was evidence enough of just how sluggish his car now was; surely he couldn't continue to hold the position for another three laps all the way to the chequered flag?

More evidence of Calado's speed (or lack thereof) arrived in the form of Luiz Razia, who suddenly swept away that earlier six second lead to close right up on the quartet. Razia had the additional benefit of having had a quiet middle race looking after his tyres, and now that he called on them to deliver attack speed they were up to the challenge and the Arden went to work, quickly dismissing first van der Garde at turn 2 on lap 21 and then Chilton at turn 12 for third.

Up ahead, Leimer's focus was on Calado. On the final lap he chose turn 12 for his own lunge for the lead - only to lock up and overshoot the chicane. That put him in the lead, but the rules mandated that he had to give the position back or face a far costlier post-race penalty. Now he faced a big headache, of how to hand the lead back to Calado in the remaining half lap of the race without also handing second on a plate to Razia.

He just about managed it, and fell into line astern with the Lotus in the run down to turn 17 hoping to have one last chance to attack for the lead. But Razia had the pace and grip to run around the outside of them both into the hairpin, and then outdrove them out of the corner and all the way to the chequered flag.

"I saw Leimer having a go on Calado and they were fighting each other, and I thought 'I've got a chance now,'" Razia told the GP2 Media Service after the race. "Leimer had to give back the position to Calado, so I just took advantage of the situation, braked really late, and ran on the outside of Calado, which was a nice move, and then just took the win, which was awesome."

Perhaps unsettled by the Arden flashing past him, Leimer ended up running off the track twice which let Calado off the hook for second place. Almost unnoticed in the background, Leimer's Racing Engineering team mate Nathana?l Berthon had also managed to take advantage of the leading pack's slow late-race pace to close up, finally jumping past an unsuspecting van der Garde for fifth place as the group crossed the line.

The upshot of that thrilling finish is that despite doing the best he could to work his way back up the running order after that first lap crash, Valsecchi's championship lead over Razia has all but evaporated and he now leads by just 1pt after a Valencia outing that he will surely want to forget as soon as possible.

That won't be easy, because it was a memorable weekend's racing. If there really was something added to the water at Valencia to ramp up the excitement this year, let's hope they remember to add it again next time that the GP2 Series returns here. It's quite an addictive and potent brew.

Full Valencia sprint race results available.