Alexander Rossi says his "astronomical" fuel-saving three-stop strategy at Gateway was frustrating, but is the sort of aggressive tactic he will need to win the 2018 IndyCar title.
Rossi was the only driver to complete a three-stop strategy in last Saturday night's race after his Andretti team-mate Ryan Hunter-Reay's fuel pressure problem caused a late caution, which meant drivers either had to make a fourth stop or back off significantly to save fuel.
The lowered pace of Rossi dropped him out of the top three to seventh, before he cycled into second as his rivals made their splash-and-dash stops.
Rossi's strategy meant he took three points out of third place finisher Scott Dixon's championship lead, reducing it to 26 points with two races to go.
"You never believe that you're going to need to fuel save as much as we did," said Rossi. "You can definitely practice it and find ways to achieve better mileage, but what we were looking for at the end was pretty astronomical.
"I don't think you ever really think that that's going to be the scenario until you're forced into it, and then you've just got to think on your feet and experiment and try and make it happen.
"It was difficult to achieve what we were trying to achieve, but the #27 [car] guys have definitely done this before.
"It wasn't our first rodeo, and I definitely had confidence in the people on the pit stand who are giving me those numbers and making the calculations to make sure we can get to the end.
"It's frustrating, but you've just got to be patient with it. At the end of the day, you're relieved that it works out because always there's that thought in your mind that it would suck if it didn't.
"We're going to have to be pretty aggressive, so I wasn't going to be upset.
"I'd rather honestly finish second going down swinging and trying to win the championship than finish second and just trying to accept that."
Rossi came close to crashing out of the race at Gateway, after moving off the racing line towards the wall and becoming unsettled on lap 146 of 243.
The Andretti driver was being passed on the inside by Will Power, and his car snapped sideways before Rossi straightened it out just before he slammed into the wall.
"I said a lot of bad words," Rossi said when he asked about the moment.
"It was one of those ones where I'd pretty much given up and it came back by the grace of God.
"I was on the brakes and ready to hit the wall. So, it just kind of corrected itself."