Rossi topped the 45-minute session around the fabled 4.048-mile road course with a best lap of 1m41.9112s.
While the track is much faster on the racing line, thanks to the track’s first full repave since 1995 that took place last October and November, there’s a huge grip disparity off-line which has been catching out the unwary if they run wide.
The session was red-flagged after just seven minutes when championship leader Alex Palou flew off the track backwards at the final corner and slammed hard into the tyre barrier as he spun, severely damaging the right side of his car. The Spaniard had just set the fastest time of the session at that point at 1m42.1368s, but his Chip Ganassi Racing team have less than two hours to repair it before qualifying.
“I was just trying to push to see where the limit was,” Palou said. “I didn’t wanna crash, obviously, hopefully, we have enough time [to fix it] as the guys are going to have to work a lot now. It’s not ideal, we lose a new tyre run, but the car is fast.”
Upon the resumption there was an even more shocking incident, as Ganassi’s other star Scott Dixon – who had just spun on the exit of Canada Corner and let Romain Grosjean pass before getting back up to speed – suddenly swerved into the path of Team Penske’s Will Power, who was on a hot lap.
The pair collided, smashing the left-front wheel from Dixon’s car before they both slammed into the concrete wall. Power, whose car suffered huge damage to three corners, immediately radioed: “What the ****? What the ****?”
Power then got out of his car, removed his helmet and shoved an apologetic Dixon in the shoulder as he remonstrated with his fellow Antipodean. The pair then discussed the incident in the medical car on the way back to the infield care centre, where they were given a clean bill of health.
Santino Ferrucci, A.J. Foyt Enterprises Chevrolet
Photo by: Jake Galstad / Motorsport Images
A third red flag was required when Santino Ferrucci spun and stalled his AJ Foyt Racing car at Canada Corner, just after a third Ganassi driver, Marcus Ericsson, went off at the final corner and just missed the barrier. Andretti Autosport’s Colton Herta earlier suffered a wild spin at Turn 7, during which he clipped an advertising sign but was able to return to the pits.
Alex Zanardi’s all-time fastest race lap of 1m41.874s was dipped under at the halfway point, with Arrow McLaren’s Felix Rosenqvist going to the top of the times with a 1m41.2572s on primary tyres.
Herta then took over with 1m41.0584s, a tenth up on Friday pacesetter Alexander Rossi (McLaren). Rossi then turned the tables, going 0.147s faster on his final lap of 1m40.9112s on primaries, while Herta spun at Canada Corner to cause a fourth red flag.
Simon Pagenaud (Meyer Shank Racing) then caused a final red by going off at the final corner in the closing moments of the incident-packed session.
Rosenqvist stayed third, just ahead of David Malukas (Dale Coyne Racing), Marcus Armstrong (Ganassi), Ferrucci, Pato O’Ward (McLaren), Kyle Kirkwood (Andretti), Scott McLaughlin (Penske) and Rinus VeeKay (Ed Carpenter Racing).
Dario Franchitti’s qualifying track record of 1m39.866s will be tested in qualifying later at 12:55pm local time (6:55pm BST).