Having led the lion’s share of the final stint and been swallowed up on the penultimate restart, Rosenqvist restarted the one-lap dash to the chequered flag in third.
His Meyer Shank Racing teammate Marcus Armstrong led the race while Team Penske’s David Malukas was second.
On the restart, Malukas got the jump on Armstrong before Rosenqvist went to the outside of the New Zealander.
The Swede ran around the outside at Turn 1 and 2 all the way down the back stretch through Turn 3 and cleared him out of Turn 4 before hunting down Malukas for the lead.
Rosenqvist won the duel by just 0.0260s in the closest-ever finish to the Indianapolis 500, stunning onlookers – not only for the tight margin, but also for his ability to go around the outside.
Never before in the DW12 era had such a move paid off.
Speaking in the days after the win, Rosenqvist revealed how a lack of tyre wear and rubber build-up meant the outer lanes were relatively clean.
He credited the series’ tyre manufacturer Firestone for bringing a better compound to the speedway.
“It was pretty much a Hail Mary moment,” Rosenqvist told Speed.
“I knew the high line was better than it had been previously, because there weren’t any marbles all day. Even when we ran green, it didn’t build up.
“I did a couple of moves on the high line, pretty deep into a green stint and it worked. So I was like, ‘Let’s keep this in the pocket’.
“I saw (Santino) Ferrucci, he did an incredible restart. I was on the high line and he was on the third lane and I was like ‘Oh my god’.
“I’ve lost many races here because I got trapped on the inside, so basically the whole strategy was you’ve got to be on the high line.
“It was kind of an easy choice because you have no real option. If you have the run, let the run continue – and if it ends in the fence or it ends with someone else winning, that’s what it is.
“It just worked. It was incredible.”
Recounting the final lap of the 2.5-mile course, Rosenqvist said it was the sort of finish he and many drivers had dreamt of.
“David, he pulled a pretty big gap out of [Turn] 2. He was doing the snake on the back straight, and it was crazy,” said Rosenqvist.
“I was next to Marcus, and every time he (Malukas) swerved to the right, my car was pulling a little bit, then he went to the left and Marcus’ car [got a tow].
“It was like a Fast & Furious moment.
“Then when I did Turn 3 flat I really started to suck up quickly to him (Malukas) and built that momentum.
“I had a lot of momentum coming out of [Turn] 4 already. He swerved down and right as I crossed behind his car, it just felt like another gear.
“I honestly didn’t think at the time it was going to do it.
“I’ve never seen anyone win it like that. I think that’s the way we think we’re going to win it, but it never happens.
“It actually ended up the way you dream about it.”
Rosenqvist will have very little time to dwell on his win.
IndyCar resumes this weekend with the Detroit Grand Prix on May 30-June 1, with coverage live and exclusively on Stan Sport.
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