The Dane’s rise to the top spot came on a set of alternate, red sidewall tyres with his Honda-powered Rahal Letterman Lanigan Racing entry, putting down a flying lap of 58.1776s around the 1.964-mile, 12-turn natural terrain road course.
It was only the second time Lundgaard led a practice session in the IndyCar Series, having previously done so last year on the streets of Nashville.
Andretti Autosport’s Kyle Kirkwood ended up second, trailing Lundgaard by 0.1470s.
Championship leader Alex Palou was third quickest overall – and on the alternates – at 0.779s off the top spot. The Chip Ganassi Racing driver did lead a portion of the early running on primary, black sidewall tires. The Arrow McLaren duo of Pato O’Ward and Felix Rosenqvist ended up fourth and fifth, respectively.
Dale Coyne Racing’s David Malukas was sixth, followed by the No. 28 Andretti Autosport entry of Romain Grosjean.
Rinus VeeKay, who ended up eighth-fastest overall, was the fastest on the primary tyres. The Dutch driver slapped together a lap of 58.783s with 20 minutes remaining before being dethroned by Lundgaard’s quick lap on the alternates, which began a chain reaction of drivers switching to the preferred rubber.
Alexander Rossi came away ninth, providing Arrow McLaren with all three of its entries in the top 10.
Josef Newgarden was the best representative for Team Penske in 10th, 0.5957s behind Lundgaard.
Juri Vips, who is making his IndyCar debut in the No. 30 Rahal Letterman Lanigan Racing Honda, put in a respectable effort to finish 15th. Defending race winner and pole-sitter Scott McLaughlin was 16th of the 27 cars.
The first red flag came just under 20 minutes into the session when Rosenqvist dropped wheels in Turn 12 before sliding nose-first into the tyre barrier, albeit with light contact.
Ed Carpenter Racing’s Ryan Hunter-Reay had an off entering Turn 12, with the backend snapping out briefly, which was enough to drift him off course before catching it and returning to the track, 25 minutes into the session.
A second red flag came out moments later after Santino Ferrrucci spun at the exit of Turn 6 and stalling at Turn 7. However, he was able to continue after the AMR Safety Team helped re-fire the No. 14 AJ Foyt Racing Chevrolet.
The issues continued to persist for Hunter-Reay, who brought out a third stoppage with roughly 40 minutes remaining in the session. The Floridian was pushing through the final section and drifted wide and was darting into Turn 12 when the backend snapped once more, and he ended up stalled coming onto the frontstretch.
Fortunately, he didn’t make any contact and, with assistance, was able to continue on.
Team Penske’s Will Power spun out of Turn 2 with 27 minutes left but was able to quickly whip around and continue on and no impede the session. With just under six minutes left, Colton Herta ended up off course in Turn 6 pushing in a late run on the alternate tire compound before returning his Andretti Autosport Honda to the pits.
Hunter-Reay has been handed a six-position starting grid penalty by IndyCar officials for an unapproved engine change at the previous round in St. Louis.