Dan Wheldon made a fuel gamble in the late stages of the Iowa Corn 250 pay off handsomely as he celebrated his 30th birthday with a second victory of the 2008 IndyCar Series season.

The Briton, who had survived a heavy practice crash with Bruno Junqueira on Saturday, was never a factor at the very front until his Target Chip Ganassi team took the risk of leaving him out on the penultimate yellow of the afternoon, leaving fate to fall his way.

Up to that point, that race appeared to be between the series' two leading Brazilians, as Helio Castroneves and Tony Kanaan took it in turns to lead, and Marco Andretti, who caught and eventually passed the pair halfway through the game.

Castroneves had taken the early advantage, jumping appointed polesitter Scott Dixon on the opening lap, but Kanaan was never far behind, having also passed the Kiwi in the opening couple of laps. By lap eight, the pair were running side-by-side, demonstrating two usable grooves on the short Iowa Speedway oval.

The duel lasted for five full laps before Kanaan edged ahead, but Helio was quick to retaliate, both men aware of the three bonus points on offer for leading the greatest distance.

Kanaan was back in front three laps later, and remained there when the first caution of the day came out for Ed Carpenter's heavy contact with the wall. The Vision Racing driver appeared to have suffered the same sort of suspension failure that had left both Marty Roth and Bruno Junqueira as spectators on race day, but his misfortune presented the first opportunity for the field to pit.

The cars returned to the track with the top of the order looking much the same, with Kanaan heading Castroneves and Andretti up to third, the vilified youngster having despatched an off-colour Dixon just as his AGR team-mate was taking the lead.

The leading trio remained unchanged through 50 laps, but Wheldon had popped back into fourth after losing ground early on and Ryan Briscoe was underlining Penske's potential by also passing Dixon. Indeed, the Kiwi was coming under pressure form Ryan Hunter-Reay, who appeared to be on the verge of another break-out performance, while Danica Patrick, AJ Foyt IV and Will Power completing the top ten.

Keen not to see his countryman racking up too many laps, Castroneves was back in front on lap 52, as Wheldon moved into third, and led to the next caution, on lap 103, when Jaime Camara coasted to a halt on the high line.

Once again, however, it was Kanaan who led the pack back on track, as Castroneves was delayed by his crew prematurely dropping the #3 car off its jacks and requiring another lift to get the right rear wheel fixed properly.

Wheldon's race was nearly jeopardised when, on the restart, he indulged in a little wheel-to-sidepod contact with John Andretti, but both survived to tell the tale.

The other Andretti, meanwhile, was making his play, harrying Kanaan for several laps before finally diving through into turn one on lap 135. Once on front, Marco appeared able to hold position comfortably, only to be thwarted when Mario Moraes spun attempting to enter pit-lane. The ensuing caution not only allowed the pack to close up on the #26, but the following pit-stops again saw Kanaan return to the lead as Andretti was delayed by a sticking airline.

The American hope was not alone, for Oriol Servia, Vitor Meira - who had received an early penalty, got another for clipping one of Foyt's hoses - and John Andretti were also delayed.

Castroneves, however, was right back in the fight, and wasted no time in repassing Kanaan at the restart, while Hunter-Reay continued to make ground, ducking under Texas nemesis Andretti later in the lap. Only a few flying laps were possible, however, before a 'bloody loose' Enrique Bernoldi spun the second of the Conquest cars, bringing out the yellows for a fourth time.

It was now that the shape of the race turned, as Wheldon, Hideki Mutoh, Danica Patrick and Ernesto Viso bucked the trend by staying on track while the rest of the field pitted. Although Viso blinked and stopped a couple of laps later for a top-up, the leading trio continued to hold station at the front of the field until the lap 196 restart.

That proved to be a false start, with Moraes finally doing terminal damage to the lone Dale Coyne entry against the turn two wall, and the every lap under yellow played into the hands of the risk-takers.

Wheldon continued to lead following the next restart but Kanaan, having made his way back into third, saw his hopes of catching and passing his former team-mate evaporate as the rear of the 7-Eleven car came around in turn one on lap 211, slamming the Brazilian into the wall in a replica of his 2007 exit at the same track.

No-one of note stopped under the lengthy caution and, after the attempt at a restart on lap 225 was again waved off, it became clear that it was now a race to the end. Wheldon had rookie Mutoh in close attendance, with Andretti leading the chase.

Castroneves, however, was no longer a factor, the Penske man seeing Power, Hunter-Reay, Briscoe, John Andretti and Justin Wilson all file past in quick succession as he reported a rapidly deflating right front tyre.

The decrease in the Brazilian's pace almost resulted in another yellow as Viso was caught out by the differential and only just managed to pull his HVM entry up in time to avoid collecting the back of the Penske in traffic - a plume of smoke from nose wing making contact with tyre underlining the narrowness of the escape.

Castroneves bowed to the inevitable at the end of the lap, leaving the battle for honours to be fought out between Wheldon, Mutoh and Andretti. The Briton did not appear to be under any great threat, especially as Andretti began to exert serious pressure on second place.

The AGR machine seemed to have the better pace through turns one and two, but not enough to make a move stick before the pair got to three and four. Time after frustrating time, the Blockbuster machine ducked to the outside without success and, then, after one last attempt two laps from home, had to check up, almost falling into the clutches of the recovering Dixon, showing his best form of the night.

Freed from the attention behind, Mutoh made a play for the victory, but Wheldon, having watched his Ganassi crew build up a fresh car for him overnight, repaid the efforts by holding on for his first victory since Kansas.

Just 0.1430secs separated the top two at the flag, with Andretti also less than a second from the leader. Dixon and Foyt claimed fourth and fifth - the former to bolster his points leader, the latter to record his best result of the year - having both passed Patrick on the run to the flag.

Briscoe, in seventh, Hunter-Reay, Power and Graham Rahal rounded out the top ten, with Andretti Sr, Wilson and Viso the remaining cars on the lead lap.