Moments after the race resumed, Danica Patrick’s car slid sideways, starting a chain reaction that knocked out the cars of Will Power and Takuma Sato.

Officials reverted to the race order that existed before the final restart, leaving Oriol Servia of Spain in second place and Scott Dixon of New Zealand in third at the 225-mile (362-kilometer) New Hampshire Motor Speedway.

After the race, Brian Barnhart, IndyCar’s vice president of competition, said he made the wrong call to resume the race in such conditions. He said he received input from his group of spotters and officials but said it was a difficult decision to make because the rain was very light.

“As soon as you had the guys stand on the gas out there, you saw right away it was the wrong decision,” he said. “At that point in time, you’re just kind of sick to your stomach and realize it was an error on race control’s standpoint and, clearly, my fault.”

Power, second in the IndyCar series point standings, was irate as he left his car and flashed an obscene gesture that was caught on camera.

“It was no condition to race in. Shame on him,” Power said, referring to Barnhart. “We worked so hard for that all day. I’m ashamed of myself for losing it. I have to say I was as angry as I’ve ever been when I got out of the car.”

Michael Andretti — owner of Andretti Autosports, which has Hunter-Reay and Patrick — was also livid. “This is the worst officiating I’ve ever seen,” he said.

Servia said he should have been declared the winner because he took the lead during the final restart. He also criticized the decision to restart the race in the first place.

“It was really wet out there and we shouldn’t have gone out,” he said.

Dixon said he also passed Hunter-Reay during the final restart and should have finished second.

“I just don’t understand race control’s thinking,” Dixon said. “It isn’t make things up as you go racing. It is IndyCar racing with rules.”

Barnhart said “it was the right thing” to revert to the order before the restart because he had made a bad decision that put drivers in jeopardy and caused costly damage to several cars.

Dario Franchitti led for 115 of the 225 laps before being hit from behind by Sato, ending his race on the 119th.

Hunter-Reay then took the lead and held it most of the way for his fifth win in 113 IndyCar races. He came in third in two of his three previous races and now has five consecutive top 10 finishes after managing just one in his other eight.

He said he wished his win “was in a little bit different way, but we’ll absolutely take it after the year we’ve had.”

The start of the race was moved up by a half hour in hopes of avoiding rain predicted for late in the afternoon.

But the crashes began on the very first lap when Mike Conway spun sideways coming out of Turn 2 and hit Graham Rahal. Both ended up on the grass and were out just seconds into the race.

Then, moments after the first restart, Helio Castroneves also spun coming out of Turn 2. He continued after repairs but never was a factor.

A light rain began falling on about the 70th lap and the yellow flag came out six laps later because of moisture on the track. After 33 laps under the caution flag, the race restarted with Franchitti in the lead followed by Sato and Servia. Then Franchitti was knocked out.

The last caution flag came out on the 206th lap because of more moisture on the track.

“It was a strange day,” Hunter-Reay said, “but sometimes racing is strange.”