The two Penske Racing Acuras led the Daytona 24 Hours after one hour of racing.
The #6 Acura ARX-05 driven by Juan Pablo Montoya held a slender lead of seven tenths over team-mate Ricky Taylor in the sister car after 36 laps of the opening round of the IMSA Sportscar Championship.
The Acuras moved ahead of the leading Mazda RT24-P late in the opening hour.
Montoya jumped pole winner and early leader Oliver Jarvis during the first pitstop cycle and then Taylor moved past the Mazda a couple of laps later.
Jarvis was just three tenths behind Taylor at the one-hour mark, while Filipe Albuquerque had brought the #5 Action Express Racing Cadillac DPi-V.R through to fifth from 11th on the grid.
Top LMP2 car was the Performance Tech Motorsports ORECA-Gibson 07 with Kyle Masson at the wheel.
The GT Le Mans class was led by Nick Tandy in the fastest of the CORE Autosport-run Porsche 911 RSRs.
The Briton moved ahead of the #3 Chevrolet Corvette C7.R during the first round of pitstops.
Third and fourth places were held by the two Rahal BMW M8s driven by Connor De Phillippi and John Edwards.
Both the second Porsche with Earl Bamber and the #67 Ganassi Ford GT in which Ryan Briscoe had run in third position lost time with technical issues.
GT Daytona was led by the Meyer Shank Racing Acura NSX GT3 with Trent Hindman.