2019 Oak Tree Grand Prix

In GTD, the #33 Mercedes-AMG Team Riley Motorsports of Ben Keating and Jeroen Bleekemolen took their first win of the season.

[2] It was the sixth consecutive year the event was held as part of the WeatherTech SportsCar Championship.

The 2019 Oak Tree Grand Prix was the tenth of twelve sports car races of 2019 by IMSA, and it was the sixth of seven rounds held as part of the WeatherTech Sprint Cup.

[4] As in previous years, it would be the second of two GT-only rounds of the IMSA SportsCar Championship, in which only the GTLM and GTD classes competed.

[5] On August 15, 2019, IMSA released a technical bulletin regarding the Balance of Performance for the race.

In GTD, Scott Hargrove returned to Pfaff Motorsports after Dennis Olsen and Matt Campbell filled in the previous two rounds.

[9] Starworks Motorsport withdrew from the event following continued performance issues with its Audi R8 after competing at Road America.

[11] The first practice session took place at 11:45 am ET on Friday and ended with Laurens Vanthoor topping the charts for Porsche GT Team, with a lap time of 1:41.296.

[12] The second practice session took place at 4:30 PM ET on Friday and ended with Patrick Pilet topping the charts for Porsche GT Team, with a lap time of 1:41.234.

[18] The GTD class was topped by the No.14 AIM Vasser Sullivan Lexus RC F GT3 of Jack Hawksworth with a time of 1:43.783.

44 Magnus Racing Lamborghini of Andy Lally stopped on track with a mechanical problem.

[18] The third and final practice session took place at 8:35 am ET Saturday was held on a wet track.

[25] Saturday's early afternoon qualifying session was divided into two groups that lasted 15 minutes each.

All cars were required to be driven by one participant and the starting order was determined by the competitor's fastest lap.

[28] IMSA then arranged the grid so that the GTLM field started in front of all GTD cars.

12 Lexus on the grid's front row with his best lap being 0.324 seconds slower, and Richard Heistand drove the No.

[30] Tandy was sixth after spinning at turn twelve, and made contact with the barrier leaving damage on the left side.

[40] The final results of GTD meant Farnbacher and Hindman extended their advantage to 37 points as Robichon took over second position.

[40] Porsche and Acura continued to top their respective Manufacturers' Championships, while Porsche GT Team and Meyer Shank Racing kept their respective advantages in their Teams' Championships with two rounds left in the season.