Torrential rain soaked the teams on the grid, forcing everyone onto wet-weather tyres, and Sutton was the master of the conditions in his Motorbase Performance-run Ford Focus ST.
He had already made up one position when the safety car unleashed the field after five laps of assessing the conditions, thanks to Aron Taylor-Smith pitting his Power Maxed Racing Vauxhall Astra with a technical problem.
Once the race got going, reversed-grid poleman Ronan Pearson eased away from the field on his local circuit at the wheel of his Excelr8 Motorsport Hyundai i30 N.
A ferocious battle for second between Ricky Collard (Speedworks Motorsport Toyota Corolla) and Dan Lloyd (Team Hard Cupra Leon) got spicey after two laps of green-flag action.
They rubbed panels as they raced down the start-finish straight, and Lloyd secured the corner into Duffus Dip, while Collard launched off the inside kerb and into the West Surrey Racing BMW 330e M Sport of Stephen Jelley, delaying both and allowing Sutton to slip through into third.
The safety car appeared again to allow marshals to extract Nick Halstead’s Hyundai from the gravel at the hairpin, and it took one and a half laps of racing before Sutton got past Lloyd and into second place on the exit of the chicane.
By the end of the lap, Sutton was 1.398 seconds adrift of Pearson, but he quickly reeled in the Scot.
At the end of the following tour, Pearson ran wide at the hairpin, and Sutton moved into the lead.
Pearson remained in second place for six more laps before Josh Cook, charging from eighth on the grid, moved his One Motorsport Honda Civic Type R in front on the run to the hairpin.
Then, on the final lap, BTCC rookie Pearson allowed title-chasing team-mate Tom Ingram through into third at Clark, a situation the reigning champion described as “I feel like I just kicked a puppy!”
Ahead of them, Cook briefly trimmed the gap to Sutton, but the leader responded with a new fastest lap and took the chequered flag with a 9.636s advantage.
After his reversed-grid disasters in the previous two rounds at Oulton Park and Croft, Sutton said: “We’ve got over our race-three hurdle, and what better way to do it than with a win?
“I needed that, just for myself,” he added after taking a 39-point championship lead over Ingram. “The thing was on absolute rails.”
Both Cook and Ingram had moved up a couple of positions after the final restart when disaster struck the WSR BMW squad – Jake Hill got onto a wet patch into the hairpin and tapped fifth-placed team-mate Jelley into a spin, bringing both cars effectively to a halt.
Hill recovered first, but another incident – he ran wide into the gravel at the hairpin – restricted him to 14th place at the finish.
Lloyd was running fifth with four laps remaining when he ran wide at Duffus Dip defending from Collard, and was forced to concede positions to the Toyota and the sister Hard Cupra of Dexter Patterson.
Collard then had to fend off the fired-up Patterson, running strongly on his home circuit, while another Scot, Aiden Moffat (One Honda), also got ahead of Lloyd for seventh.
George Gamble (Speedworks Toyota) and Dan Cammish (Motorbase Ford) rounded out the top 10.