Josef Newgarden has extended his IndyCar Series lead with victory in Iowa while a strong result for Will Power went begging due to a pit entry indiscretion.

Newgarden (#2 Chevrolet) led the vast majority of the 300-lap race, which was at one stage suspended due to rain, while Team Penske team-mate Power (#12 Chevrolet) ultimately finished a lap down.

Scott Dixon, on the other hand, dug himself out of a hole by getting back onto the lead lap and ultimately finishing second, with James Hinchcliffe third, pole-sitter Simon Pagenaud fourth, Spencer Pigot fifth, and Alexander Rossi sixth.

Power took the lead from the outside of the front row when the race eventually got underway several hours late due to rain, while Takuma Sato had an early spell in second position before being re-passed by Pagenaud (#22 Team Penske Chevrolet) and Newgarden.

A Sage Karam (#31 Carlin Chevrolet) spin caused a Caution and Newgarden passed Pagenaud shortly after the Lap 24 restart, while Dixon (#9 Chip Ganassi Honda) continued to run around the back of the top 10.

When Power got held up by traffic, Newgarden nabbed the lead on Lap 49, and the race was red flagged a couple of laps later due to more rain.

For the restart, Newgarden led Power, Pagenaud, Rossi (#27 Andretti Autosport Honda), and Sato, while the Chip Ganassi Racing crew got Dixon back up to 11th in the pits after he had dropped as far back as 16th.

Sato and then Santino Ferrucci (#19 Dale Coyne Racing Honda) got by Rossi, Ferrucci having battled with him for several laps, and while Newgarden and Power pulled away, the top six positions remained unchanged until past Lap 100.

That was when Ferrucci, Rossi, and then Hinchcliffe (#5 Schmidt Peterson Honda) would pass Sato, then Rossi would take fourth position from Ferrucci on Lap 112.

Hinchcliffe also got Ferrucci on Lap 119, just as Sato made a pit stop out of sequence having lost all pace from the #30 Rahal Letterman Lanigan Honda.

It meant that he was second when the rest finally pitted again just before the halfway mark, with Newgarden in front and Power third from Pagenaud, and Pigot (#21 Ed Carpenter Racing Chevrolet).

Rossi was eighth and Dixon a lap down in 17th.

Power took second position off Sato on Lap 148 while Pagenaud dropped back to sixth, behind Ed Carpenter (#20 Ed Carpenter Racing Chevrolet), and they ran that way until Sato was an early pitter again on Lap 177.

The Japanese driver was out of sequence when he came up on the back of Power on the race track 10 laps later, but when he propped and got out of the groove, he was clouted by Karam, which brought out a Caution.

With the field pitting, Newgarden led Power, Pigot, Pagenaud, and Carpenter, Rossi was back on the lead lap in seventh, and Dixon was back on the lead lap in 14th.

It was not long before Pagenaud passed Pigot for third and Hinchcliffe passed Carpenter for fifth.

Another pit stop cycle came with about 50 laps remaining and that would be crucial for Power, who made a mess of pit entry, nearly hit pit wall on the way in, and would ultimately have to come in for a hold penalty.

As he did, Carpenter spun and hit the wall, triggering what would be the final Caution.

Dixon had risen to third having not yet pitted under the cycle so he used the Caution to do so, and emerged in sixth position, behind Newgarden, Pagenaud, Hinchcliffe, Pigot, and Graham Rahal (#15 Rahal Letterman Lanigan Honda).

Newgarden stayed in the lead for the 27 laps which remained after the restart, while Dixon charged to second on fresher tyres and Hinchcliffe, who got as high as second, ended up third.

Power was 12th for the final restart but did not make the best of it and dropped to 15th, where he would stay until the finish.

Newgarden’s lead is 19 points over Rossi with the next round at Mid-Ohio on July 26-28.

Race results: Iowa

Race winner: 300 laps
(C)hassis: D=Dallara | (E)ngine: C=Chevy, H=Honda | (T)yre: F=Firestone

Series points