The 22-year-old endurance racer from Forfar, partnering Adam Balon in the number 72 Lamborghini Huracan Evo GT3, prepared by Barwell Motorsport, endured a punishing day at Oulton Park in Cheshire.
In the opening 60-minute race Mitchell, a Lamborghini factory driver, was forced to nurse the car home.
First he was hit from the rear by a Mercedes.
The impact, which happened with around 20 minutes of the race remaining, resulted in rear left tyre damage from the shattered bodywork and forced the Scot to significantly reduce his race pace.
“Adam did a super job in his opening 30-minute stint, but shortly after I took over the car I was hit from behind,” the 2020 British GT champ explained.
“The car then suffered a tyre problem due to body damage rubbing against the tyre wall, which meant I was around two seconds a lap slower than what my normal race pace would be.
“After the contact it was a case of driving as defensively as possible to ensure we scored as many championship points as we could. In the end, finishing ninth was an achievement.”
Mitchell started race two from third on the grid, but five minutes in to the race the safety car was deployed following an incident.
When the race restarted following a 16-minute delay, the circuit was hit by a heavy rain shower.
And within minutes, and following another short safety car period, the race was red flagged and stopped following yet another incident.
After a 40-minute delay while repairs were made to crash barriers, and with Balon now behind the wheel for the remaining 25-minutes of racing, the number 72 Lamborghini restarted in fifth place.
But almost immediately their car was served a 10-second stop-go penalty following an earlier unavoidable incident due to the adverse weather conditions.
The delay dropped the duo to 12th overall.