Helio Castroneves ended a three-year IndyCar win drought with victory for Penske at Iowa Speedway.
Castroneves took the lead from polesitting team-mate Will Power in traffic early on, with Power struggling to match his team-mate’s pace.
Penske was then able to make use of cautions for crashes for Mikhail Aleshin, Carlos Munoz and Conor Daly to make all of Castroneves’ first three pitstops under yellow.
With just under 100 laps to go the red flag was brought out briefly due to light rain, and when the race restarted it was a case of who would pit first.
Ed Carpenter Racing elected to pit JR Hilderbrand from second, which allowed him to make use of the undercut and emerge ahead of Castroneves in the closing stages.
But traffic played a crucial role and allowed Castroneves on fresher tyres to retake the lead and ultimately secure the win.
That win leaves just eight points between Castroneves and Scott Dixon, who finished in eighth, in the drivers championship.
Ryan Hunter-Reay was third with an impressive drive from 15th on the grid, while Power finished fourth having been overtaken by the Andretti Autosport driver in the closing stages.
Graham Rahal was fifth having started from 10th, also making use of the earlier cautions to jump drivers in the pitstops.
Josef Newgarden came back from starting 16th to finish sixth, with fellow Penske driver Simon Pagenaud also making progress from a disappointing qualifying position as he came from 11th to seventh.
Tony Kanaan and James Hinchcliffe rounded out the top 10 behind Dixon.
RESULTS – 300 LAPS:
|1||Helio Castroneves||Team Penske||Dallara/Chevrolet||1h55m11.2807s|
|2||J.R. Hildebrand||Ed Carpenter Racing||Dallara/Chevrolet||3.9647s|
|3||Ryan Hunter-Reay||Andretti Autosport||Dallara/Honda||4.5845s|
|4||Will Power||Team Penske||Dallara/Chevrolet||5.7403s|
|5||Graham Rahal||Rahal Letterman Lanigan||Dallara/Honda||10.1811s|
|6||Josef Newgarden||Team Penske||Dallara/Chevrolet||11.0500s|
|7||Simon Pagenaud||Team Penske||Dallara/Chevrolet||12.2562s|
|8||Scott Dixon||Chip Ganassi Racing||Dallara/Honda||14.3653s|
|9||Tony Kanaan||Chip Ganassi Racing||Dallara/Honda||15.1184s|
|10||James Hinchcliffe||Schmidt Peterson Motorsports||Dallara/Honda||15.8243s|
|11||Alexander Rossi||Andretti Herta||Dallara/Honda||1 Lap|
|12||Ed Carpenter||Ed Carpenter Racing||Dallara/Chevrolet||1 Lap|
|13||Esteban Gutierrez||Dale Coyne Racing||Dallara/Honda||1 Lap|
|14||Max Chilton||Chip Ganassi Racing||Dallara/Honda||1 Lap|
|15||Charlie Kimball||Chip Ganassi Racing||Dallara/Honda||2 Laps|
|16||Takuma Sato||Andretti Autosport||Dallara/Honda||2 Laps|
|17||Marco Andretti||Andretti Autosport||Dallara/Honda||2 Laps|
|18||Ed Jones||Dale Coyne Racing||Dallara/Honda||3 Laps|
|19||Conor Daly||AJ Foyt Enterprises||Dallara/Chevrolet||Contact|
|20||Carlos Munoz||AJ Foyt Enterprises||Dallara/Chevrolet||Contact|
|21||Mikhail Aleshin||Schmidt Peterson Motorsports||Dallara/Honda||Contact|