2021 Sports Car Challenge at Mid-Ohio

This race was initially meant to be the fifth round of the 2021 IMSA Championship, until the two "West Coast Swing" rounds, located at WeatherTech Raceway Laguna Seca and Long Beach street circuit, both in California, were postponed to September due to the ongoing COVID-19 pandemic in California.

[1] On May 5, 2021, the entry list for the event was released, featuring a total of 26 cars across three classes.

In the GTD class, several teams who were scheduled to be present only at the 3-hour rounds on the 2021 calendar made their season debut, including CarBahn Motorsports and Compass Racing, the former of which was making the step up from the IMSA SportsCar Championship support category, the Michelin Pilot Challenge.

In those two races without Hardwick, Wright Motorsports built up a points lead in the GTD class.

On May 5, 2021, IMSA released a technical bulletin regarding the Balance of Performance constraints for the Mid-Ohio race.

After winning at Daytona and Sebring, the Acura ARX-05 and Cadillac DPi-V.R respectively were each given a 1.0 liter reduction in fuel capacity.

A similar change was made to the Acura NSX GT3 Evo, with a 10 kilogram weight reduction after best finishes of 11th and 4th at Daytona and Sebring respectively.

Forty7 Motorsports and Grasser Racing Team withdrew from the event prior to the first practice session.

[8] The first practice session took place at 4:30 pm ET on Friday and ended with Pipo Derani topping the charts for Whelen Engineering Racing, with a lap time of 1:11.846, ahead of the No.

[10] Jack Hawksworth was fastest in GTD with a time of 1:20.513, 0.291 seconds faster than Bill Auberlen's No.

[11] The session was red flagged early for ten minutes after Jarett Andretti stopped on track.

[10] The second and final practice session took place at 8:50 am ET on Saturday and ended with Dane Cameron topping the charts for Meyer Shank Racing with Curb-Agajanian, with a lap time of 1:10.766.

[29] WTR-Konica Minolta Acura kept their advantage in the DPi Teams' Championship while Riley Motorsports and Turner Motorsport became the leaders of their respective class Teams' Championships with nine races left in the season.