Helio Castroneves has taken his first IndyCar win in over three years claiming the Iowa Corn 300.

Castroneves led 217 of the 300 laps around Iowa Speedway, but still had to come from behind in the final stint to relegate JR Hildebrand to second, ahead of Ryan Hunter-Reay and Will Power.

The helpful timing of cautions saw most cars opt for a roughly even four-stop strategy, plus an additional spell in pit lane when light rain saw the race briefly suspended.

Power led from pole but it was his Team Penske Chevrolet team-mate Castroneves who took over the lead on Lap 20.

The two Ed Carpenter Racing Chevrolets were also in the mix early on, with Ed Carpenter himself briefly putting Power back to third.

Mikhail Aleshin wrestled his loose Schmidt Peterson Honda into a favourable position, climbing from sixth on the grid to third before losing a position to Graham Rahal (Rahal Letterman Lanigan Honda).

It was Aleshin, however, who would bring out the first Caution on Lap 57 when his car finally broke away properly over a bump and spun into the wall.

The whole field peeled off when pit lane opened, though the top five of Castroneves, Power, Rahal, Carpenter, and Hildebrand unchanged through the stops.

In the second stint, Castroneves saw off a challenge from Power to put a few tenths of a second in his team-mate, but the ECR pair were again strong early.

Carpenter quickly picked off Rahal for third, before Hildebrand again came on late in the stint and passed Castroneves for the lead on Lap 97.

Power also got by the Brazilian, on Lap 104, but was by now 2.7s behind Hildebrand.

The next Caution came on Lap 132 when Carlos Muñoz scraped the wall in his AJ Foyt Chevrolet, prompting all to make their second pit stops.

Castroneves jumped back into the lead, and Hunter-Reay swapped positions with Rahal to emerge fourth, while Carpenter had by now drifted back to eighth.

Power went high at the second restart, on Lap 143, to round up Hildebrand, and Rahal got back what he had lost to Hunter-Reay in the pits almost immediately, reclaiming fourth position.

However, Power couldn’t keep pace with his team-mate and instead found himself behind Hildebrand again on Lap 169, just before another Caution when the other Foyt car of Conor Daly also got the wall.

Charlie Kimball (Chip Ganassi Honda), who had run 15th, assumed the lead when he didn’t pit under yellows, but was eaten up on older tyres in the laps following the restart.

That meant that Castroneves led the race again, from Power, Hunter-Reay, Rahal, and Hildebrand, the latter having lost an effective two positions in the pits and another shortly after the restart.

The race took a twist when yellows flew again on Lap 197 for light showers at the 0.875mi speedway, before a short race suspension while rain cleared.

Josef Newgarden (then sixth), Simon Pagenaud (ninth), and Scott Dixon (12th), who all had disappointing qualifications, gave up track position for another pit stop for fresh tyres.

The restart on Lap 211 saw Castroneves quickly skip 0.6s ahead of Power, with Newgarden (Team Penske Chevrolet) initially making the most of his newer rubber, regaining sixth on Lap 218.

Pagenaud (Team Penske Chevrolet) moved up to seventh on Lap 229, while Dixon’s (Chip Ganassi Honda) progress was slower as the New Zealander got up to an effective ninth position on Lap 246.

Hildebrand, who held fourth for three laps during the stint, was the first to make his final pit stop when he exited the circuit from fifth position in Lap 246.

Castroneves was the next of the heavy-hitters to stop, but took another seven laps to do so and lost the effective race lead in the process.

As the stops shook out, the genuine top five became Hildebrand, Castroneves, Hunter-Reay, Power, and Rahal.

Castroneves chased Hildebrand through the traffic, and when the latter was baulked by Marco Andretti, who still needed to make his final pit stop, on Lap 268, Castroneves pounced.

The #3 driver took over not just the effective race lead but also the nominal race lead in the manoeuvre, with Andretti waiting another eight laps to pit, and put margin on Hildebrand to eventually win out by 3.9s.

The win is Castroneves’ first since the 2014 Detroit race, 54 races ago.

The rest ran unchanged, with Hildebrand second ahead of Hunter-Reay, Power, and Rahal.

Newgarden’s strategy play proved a net neutral as he finished sixth, ahead of Pagenaud, Dixon, Tony Kanaan (Chip Ganassi Honda), and James Hinchcliffe (Schmidt Peterson Honda).

Castroneves has now cut Dixon’s championship lead to just eight points, with the next stop on the calendar the Honda Indy Toronto on July 14-16.

Results: Iowa 300

(C)hassis: D=Dallara | (A)erokit: C=Chevy, H=Honda | (E)ngine: C=Chevy, H=Honda | (T)yre: F=Firestone

Note: Additional pit stop counted for most drivers due to red flag

Championship points