Herta wheeled the #26 Andretti Global w/ Curb-Agajanian Honda to a fastest average lap speed of 234.974mph (378.154km/h), slightly faster than Takuma Sato had gone in the corresponding session of 2023.

His effort knocked Larson, who is attempting the Indy 500-Charlotte 600 ‘double’, off top spot but the 2021 NASCAR Cup Series champion was still second-quickest for the day with a 234.271mph (377.023km/h) lap in his #17 McLaren Chevrolet.

However, the real form guide is found in third through seventh on the timesheet, headed up Penske’s Josef Newgarden and Scott McLaughlin, who were first through fifth respectively on non-tow laps.

Newgarden’s fastest lap of 234.260mph (377.005km/h) in the #2 Chevrolet was set without tow assistance, as was McLauglin’s 234.102mph (376.751km/h) in the #3 Chevrolet.

The same could be said for McLaren’s Alexander Rossi (#7 Chevrolet) in fifth and third respectively on a 234.006mph (376.596km/h), and Penske’s Will Power (#12 Chevrolet) in sixth and fourth respectively on a 233.864mph (376.268km/h).

Showing just how quick Penske and McLaren are, the latter also saw Pato O’Ward put the #5 Chevrolet seventh on the timesheet on a 233.748mph (376.181km/h) and fifth on non-tow rankings on a 233.370mph (375.573km/h).

AJ Foyt Racing’s Santino Ferrucci made for an all-Chevrolet non-tow top six, with Sato, this year undertaking an Indy 500-only campaign back at Rahal Letterman Lanigan Racing, Honda’s best on that metric in seventh on a 233.139mph (375.201km/h).

Herta ended up 10th on non-tows on a 233.084mph (375.112km/h) and Larson 15th on a 232.695mph (374.486km/h).

The non-tow speeds are the more relevant on Fast Friday, when boost levels are turned up to qualifying mode, because each driver is sent one-by-one for a four-lap qualifying run tomorrow.

Once again, Penske was on top, with Newgarden holding the benchmark four-lap average of 234.063mph (376.688km/h; 234.260, 233.937, 233.970, 234.087) in a top three rounded out by McLaughlin (233.623mph or 375.980km/h) and Power (233.451mph or 375.703km/h).

Dale Coyne Racing rookie Nolan Siegel became airborne when he crashed the #18 Honda just over 90 minutes into proceedings and expects that he will need a back-up chassis for qualifying weekend.

There was a smaller setback for two-time IndyCar Series champion Alex Palou, whose #10 Chip Ganassi Racing Honda needed an engine change after it began blowing smoke midway through the session.

Practice 6 starts on Saturday at 08:30 ET/22:30 AEST, followed by Day 1 Qualifications at Saturday 11:00 ET/Sunday 01:00 AEST.

Results: Fast Friday