The Indy Grand Prix of Alabama has been postponed a day because of heavy rain.
IndyCar officials called the race after a second lengthy rain delay. It will be completed Monday morning with a restart on Lap 23.
The race had been scheduled for 90 laps with a two-hour limit because of the heavy rain that contributed to some spinouts.
Newgarden and Hunter-Reay are both two-time winners at Barber Motorsports Park.
"I was calling for us not to run and I was in the easiest situation,'' Newgarden said. "I was leading the race, had the best viewpoint. We do another (16) minutes under caution and we call the thing halfway from a time standpoint, we pick up the win. It's more advantageous for us to get it in, but I didn't want to do that. I didn't think conditions were right.''
The 2-hour limit of total race time will remain in place.
Newgarden led the first 22 laps of a race he has won two of the past three years. The race restarted after a 37-minute delay because of the track conditions, but only got another few laps in before parking the cars again. The race was called after another 1-hour, 23-minute wait.
Points leader Alexander Rossi said at times he could see "absolutely nothing.'' He questioned the decision to put up the green flag after the first yellow caution, and "obviously the results of that was a car hydroplaning.''
It was the first time racing in such rainy conditions with this year's new aero kit.
"This is the first actual wet running I've done besides a Sunday morning warmup,'' Rossi said. "It was very bad (Sunday). I don't know if that has to do with the generation of the car or not.''
Information from The Associated Press was used in this report.