After three hours of intense racing, the Forfar racer’s winning gap was just 0.529secs.
Having clocked the fastest time round Silverstone in a GT3 car in practice, clocking 1min 57.100 secs, Mitchell went even quicker in qualifying, stopping the clock in 1:56.765s to set a new qualifying lap record and put the car on pole position.
Team mate Adam Balon took the opening stint in the race and led for the opening six minutes before he was nudged wide by the number 32 Lamborghini.
The contact brought a penalty for the number 32 and Balon retook the lead before pitting to hand the car to Mitchell after 43 minutes.
Mitchell maintained the lead through his first stint, navigating traffic and managing the Pirelli tyres brilliantly, before handing the car back to Balon.
The Englishman was frustratingly hampered by slow-moving traffic towards the end of his stint, but despite that Balon delivered a really strong performance to keep within striking distance of the number 88 car allowing Mitchell to achieve the undercut at the next pitstop.
With 43 minutes of the race remaining, Mitchell was back in the Lamborghini.
“Adam’s second stint was really important,” the British GT champion in 2020, explained.
“He maintained the gap to the number 88 car in front which meant I could do a few really quick laps when I got in the car to have a chance of being ahead when they pitted. Thankfully that’s exactly what happened.”
When Mitchell emerged from the pits he immediately set his personal fastest lap of the race, a 1:58.372s, and followed that up with two other super-quick laps. It meant that when the #88 emerged having completed its final pitstop, the Angus racer was three car lengths ahead.
“Managing to get ahead of the number 88 car when it rejoined the circuit after its final pitstop was the be all and end all of the race,” Mitchell admitted. “That was the result right there.”
Mitchell he fended off the number 88 car, driven by German Marvin Kirchhoefer, for the remaining 40 minutes.
“I knew I would have to soak up the pressure right to the chequered flag,” he said.
“That final stint was really tough in terms of intensity. He was within a second for most of the stint.
“But I always knew I was in control of the race and it was fantastic to cross the line 0.529secs ahead.”
The win, which boosts Mitchell’s championship standings, was the second time he has won the Silverstone 500 in three years, becoming the only driver to win it twice.
Twelve months ago he also took maximum points when he finished second, behind a car not registered for the championship.
“From this year’s championship point of view, the result is huge,” Mitchell said.
Mitchell returns to action in the British GT Championship on May 28/29 when the series returns to Donington Park.