Oliver Jarvis led Mazda Team Joest teammate Ryan Hunter-Reay by 0.445sec, the #77 Mazda RT24-P lapping the 3.56-mile Daytona road course in 1min34.753sec, with RHR’s fellow IndyCar ace Scott Dixon leading the Cadillac charge.
The Wayne Taylor Racing Cadillac DPi-V.R was, however, a further 0.45sec in arrears, 0.193sec ahead of Ricky Taylor’s best effort in one of the Acura ARX-05s run by Team Penske.
Matheus Leist was fifth in his JDC-Miller Motorsports Cadillac DPi-V.R ahead of the similar Action Express Racing entry of Filipe Albuquerque.
Juan Pablo Montoya was seventh fastest in the second Acura, while Loic Duval was eighth in the second JDC-Miller machine.
The best of the LMP2 cars, 2.6sec off the best DPi time but only 1.1sec behind Duval, was the DragonSpeed entry piloted by Harrison Newey.
The son of F1 ace designer Adrian Newey eclipsed Nicolas Lapierre's Tower Motorsports by Starworks entry by 0.428sec, while Simon Trummer of PR1/Mathiasen Motorsports was another 0.8sec in arrears in third.
A Porsche 1-2 in GT Le Mans saw Laurens Vanthoor shade teammate Frederic Makowiecki by just 0.080sec, while Daniel Serra’s top lap in the Risi Competizione Ferrari 488 was a mere 0.026sec slower in third.
Jordan Taylor, wheeling the faster of the two new mid-engined Corvette C8.Rs, was 0.6 adrift from Vanthoor’s time.
Former Indy Lights ace Franck Perera was in fine form, shooting the Grasser Racing Team Lamborghini Huracan GT3 Evo to P1 in GT Daytona class, but only 0.027sec faster than GRT Magnus teammate Andy Lally.
Andrea Caldarelli was third in the Paul Miller Racing Lambo, barely ahead of Pat Long in the Wright Motorsports Porsche 911 GT3 R.
Jules Gounon was fifth-quickest in the Meyer Shank Racing Acura NSX GT3, but teammate Shinya Micihimi brought out the red flag when he spun and stopped. Aaron Telitz was top Lexus for AIM Vasser-Sullivan in sixth.
Practice resumes at 10.30 local (Eastern) time on Sunday.