The Briton, who is substituting for the injured David Malukas in the No. 6 Arrow McLaren Chevrolet, vaulted to the top of the charts in the opening 15 minutes and was never dethroned after a flying lap of 1m38.7784s at the 3.067-mile, 17-turn circuit.
Chip Ganassi Racing’s Alex Palou, who swept Friday’s two sessions of running that totaled five hours, ended up second at 0.0524s behind.
Christian Lundgaard (Rahal Letterman Lanigan Racing), Scott McLaughlin (Team Penske) and Pato O’Ward (Arrow McLaren) rounded out the rest of a top five that was separated by 0.3407s.
Marcus Armstrong (Chip Ganassi Racing), Romain Grosjean (Juncos Hollinger Racing) and Colton Herta (Andretti Global) occupied spots sixth through eighth. Meanwhile, the Meyer Shank Racing duo of Felix Rosenqvist and Tom Blomqvist ended up ninth and 10th, respectively.
The two-hour test, one of the four sessions ahead of Sunday’s $1 Million Challenge, endured a trio of red flags.
The first stoppage happened moments after Ilott jumped to the top of the leaderboard, with repairs needed in Turn 5 after chunks of the racetrack appeared to be coming up. Following a lengthy stop that lasted nearly 49 minutes, the the session resumed.
Due to the extended break, an additional 15 minutes was added to the session.
However, it was short after Grosjean brought out another red flag with 57 minutes remaining after being stranded off course in Turn 15. He appeared to lock up the rear and drift off course.
The session resumed five minutes later, but another red flag came moments later for Kyle Kirkwood. The driver of the No. 27 Andretti Global Honda got out of shape after hitting a bump, which sent him off course and then caught air after hitting off course curbing and backed into the Turn 8 barrier, damaging the rear of his car. Fortunately, the repairs were quick and he was able to return before the session ended.
The fourth and final session is scheduled for 4 p.m. ET, with qualifying for tomorrow’s heat races to follow at 8 p.m. ET.
