Helio Castroneves has put Acura Team Penske atop the time charts in a slick, damp and cold Practice 3 at Mid-Ohio.
The Brazilian reeled off a 1:12.737 lap in the closing seconds of the 60-minute session to bump teammate Dane Cameron from the top spot and lead a 1-2 for Acura ARX-05 DPi machinery.
The No. 5 Mustang Sampling Racing Cadillac DPi-V.R of Joao Barbosa was third quickest, followed by Pipo Derani in the sister Action Express Racing-run Whelen Engineering Racing entry in fourth.
Simon Trummer, in another Cadillac DPi, completed the top-five.
A late flyer by Ryan Briscoe put the No. 67 Chip Ganassi Racing Ford GT on top in GT Le Mans, while Trent Hindman was quickest in GT Daytona in his No. 86 Meyer Shank Racing Acura NSX GT3 Evo.
The No. 38 Performance Tech Motorsports Oreca 07 Gibson of Kyle Masson led LMP2, meanwhile.
Nearly all of the times came late in the session as track conditions improved.
The session saw two red flags, both for the No. 12 AIM Vasser Sullivan Lexus RC F GT3, which had off-course excursions in the hands of both Townsend Bell and Frankie Montecalvo.
Qualifying is set to get underway at 11:40 a.m. EDT.
RESULTS: Practice 3