Penske's Josef Newgarden says he had no idea if his "risky" pass on Robert Wickens to win the 2018 IndyCar race at Phoenix in the final laps would work.
Newgarden and team-mate Will Power had moved to the front of the field in Saturday's race after Simon Pagenaud, Alexander Rossi and polesitter Sebastien Bourdais all lost out in the first pitstops with errors.
The Penske duo were later undercut by Schmidt Peterson Motorsports pair James Hinchcliffe and Wickens, but a late full-course yellow left a seven-lap dash to the finish.
While the two SPM drivers stayed out on old rubber, Newgarden opted for new tyres and, having cleared Hinchcliffe and Rossi, stormed around the outside of Wickens at Turn 1 to make the race-winning move with three laps to go.
"The last pass was risky, I didn't know how that was going to go," said Newgarden.
"The first one [the final restart pass on Hinchcliffe and Rossi] I felt pretty confident in. I analysed it. It was premeditated.
"The last one, I didn't know I had to do that.
"When I was sizing him up, I was like, 'man, this is the only way this is going to work out'. I didn't know if it was going to work, but it was good.
"The tyres make a huge difference. I had 50-lap newer tyres [compared to Wickens]. With that, with how much he had to check up in Turn 1, he gave me just enough room.
"I didn't have to get crazy high. That one I definitely took risks.
"Sometimes you have to do that in the right position, and I think it was the right time to do it."
Newgarden added that he had doubts about the race call employed by his strategist and Penske president Tim Cindric, with the team opting for an early second stop midway through the race to gamble on fuel.
That kept Newgarden in the leading pack before Ed Jones caused the final caution that set up his race win.
"Honestly, I didn't know if that was the right call," he said.
"I felt like we finally got our car where we needed to be in the final stint.
"I don't want to question Tim.
"He normally doesn't let me down, the team doesn't normally let me down. Whatever they say to do, I'm always going to do it.
"I always think, 'did we do the right thing?'. It's natural to think that, after running the race, we did the right thing.
"It was a team win tonight. I don't know that I deserved to win the race, but I think the team did.
"They did a really good job on strategy, [the] pitstops were unbelievable. I think I gained five or six positions on just the first stop, which was awesome.
"We were a top-five car tonight for sure."