Dixon topped the 30-minute session around the 11-turn, 1.786-mile Exhibition Place street course with a best lap of 1m01.3208s.
The session started in damp conditions after a rainy and foggy start to the day, but the track quickly dried out with all cars on slick tyres. After a dry-wet-dry qualifying, many drivers had an abundance of tyres to use to get a final read on degradation over a stint.
Dixon set the early pace with 1m02.7294s after 10 minutes, with polesitter Christian Lundgaard (Rahal Letterman Lanigan Racing) getting within a tenth. Team Penske’s Scott McLaughlin and Felix Rosenqvist (Arrow McLaren) then got into an entertaining spat where they ran side-by-side, corner after corner.
Colton Herta, who will start 14th for Andretti Autosport, produced two laps in the 1m02.7s in succession, just 0.032s off Dixon for P2 at the halfway point, with the majority of times set on the primary tyres.
Lundgaard switched to the softer alternate rubber and took P1 with 1m02.7137s, shortly before David Malukas topped that with 1m02.7002s on the green-sidewalled Firestones.
Callum Ilott, Juncos Hollinger Racing Chevrolet
Photo by: Jake Galstad / Motorsport Images
Callum Ilott (Juncos Hollinger Racing) then enjoyed a turn at the top with 1m02.5856s, before Alex Palou (Ganassi, the points dominator who will start down in 15th today) beat him with 1m01.8695s with six minutes to go. Josef Newgarden (Penske) then set 1m01.6161s before Dixon retook P1 with 1m01.3208s – which stuck as the quickest time of the session.
Kyle Kirkwood (Andretti) ended the session in P2, just 0.06s slower, ahead of Newgarden, Herta, Palou and Lundgaard.
Santino Ferrucci (AJ Foyt Racing) had an early off at Turn 3 and continued after gently nosing into the tyrewall, while Andretti’s Devlin DeFrancesco – the sole Canadian in the field – also overshot at that point of the track. He rejoined an ended the session in an encouraging eighth place.
Tom Blomqvist, who makes his IndyCar debut for Meyer Shank Racing this weekend, was 19th fastest, while Rosenqvist slipped to last.
The race starts at 2:00pm local time, with only a slight chance of rain in the forecast.