Rosenqvist lapped his Honda-powered MSR machine in 1m00.339s, almost half a second quicker than his rivals after his off-season switch from Arrow McLaren.
The rest of the top 10 were covered by less than three tenths, which moved fourth-fastest driver Will Power of Penske to state that “Felix is on another planet out there”.
“Kinda surprised,” said Rosenqvist. “We were really good out of the gates, really confident, which I’ve been since pre-season testing. And on the reds we just took another step.
“The car was just really good. It’s been really nice to come to Meyer Shank Racing, it’s been a really super-easy transition. At McLaren it was a big learning curve with the car, but it’s been the opposite here, it’s clicked since Day 1. It’s a smaller group, so it’s easier to get up to speed.
“A really smooth start for us, we were a bit unsure where we’d stack up when we started pushing, we thought we’d be quick but not that far ahead.
“I think on the street tracks we’ll be good. I feel more confident on those kind of tracks.”
Behind McLaren’s Pato O’Ward, Marcus Armstrong was the fastest of the five Chip Ganassi Racing drivers, just 0.007s off the second spot.
“The car started off in a difficult spot,” said Armstrong, who was third fastest. “And, to be fair, it didn’t actually feel that good at the end. But we’re still up there, so what more can I ask for?”
Power, who was fourth quickest, said: “Felix is on another planet out there, but everyone else is really close. I thought he’d do very well in that environment, he’s very quick. No surprise for me.
“Car feels good, everything feels calm and that means I’ve got something in reserve.
“I’m very motivated, I’m really pissed off about going winless last year, I’m putting a lot of emphasis on that. It’s expected to perform at this team, I’ve had my head down, I’m thinking about nothing else than competing at a very high level this season.”
