Rosenqvist started the race as twelfth, but climbed all the way up to a podium position during the competition.
It's been a while since I took a podium position, I had to ask over the radio where I should park the car. It feels like we've finally got what we deserve this season and hopefully it will continue like this, says Rosenqvist in Viaplay after the race.
In front of him, Rosenqvist had Honda colleague Alex Palou, who leads the overall standings in Indycar Series.
It was a crazy race. I couldn't have been happier, says Palou after the win.
McLaren's Santino Ferrucci came third.
The competition's other Swede, Marcus Ericsson, finished in 21st place.