Despite back-to-back Indy 500 wins, the last two years have been the American's worst at Team Penske.
Newgarden is currently tenth in the standings, but with a spate of his favored oval tracks coming up, the 33-year-old refuses to rule himself out of contention.
Newgarden 'surrendered to fate' but says anything is possible
With eight rounds to go, Newgarden is 143 points adrift of championship leader Alex Palou.
Five of those remaining races are on oval tracks, the circuit type around which Newgarden has dominated IndyCar in recent years.
However, he is not getting carried away. "We’re surrendered to fate in a lot of ways," the Team Penske driver told RACER.
"It’s been a really hard year. Indy was amazing; everything about it was incredible for the team. And then when you look at the championship, it’s been the opposite.
"It’s been worse than feast or famine. This one’s been a super roller coaster. Super highs and lows. So, we are where we are.
"The last two events in particular were really tough. Laguna [Seca] ended up being a bust, and then Mid-Ohio turned into a bust. So that’s a lot of why we’re 143 back. That’s really bad."
Newgarden placed 19th at Laguna and then 25th at Mid-Ohio, a disappointing points haul which has almost put him out of sight of the leaders.
But with two championships to his name, he is not giving up on a third, saying: "I’m not going to say we can’t win the championship. Anything’s possible, and I always believe that."
"What I don’t want to rely on is Iowa," he said ahead of the double header at the oval Speedway.
"I think most people, they look at us and they go, ‘Well, this is going to help you.’ But I’m more worried about Portland [road course] and Toronto [street circuit].
"We can be great here. We can be great on the other ovals. That’s good, but it’s not going to be enough. We’ve got to have a great Toronto. We’ve got to have a great Portland."
A late-season rally could see Newgarden storm back to take the title, but as he admits, he will need to be virtually flawless throughout the rest of the calendar.