Jack Goff made the most of his reverse grid pole position in Snetterton race three to claim his first win in the BTCC and MG's first of the 2015 season.
The Buckinghamshire native did not crumble under pressure from points leader Jason Plato, leading every lap of the race on his way to the chequered flag.
While Goff headed the field at the start after a strong getaway, Sam Tordoff endured another difficult launch from second, with Andy Priaulx and Plato taking advantage.
Plato, having himself slipped behind Priaulx into turn one, then stuck his car round the outside of three-time WTCC champion at Brundle and emerged ahead, setting out after the race leader.
But Goff, who built up a two-second lead while those chasing him fought amongst each other, comfortably managed the lead as the race approached and passed the halfway point.
Plato began to make up ground in the final minutes and closed in on the final lap, but Goff held on by three tenths.
Priaulx had to deal with pressure from Tordoff, but stayed ahead of record his second consecutive third place.
Goff's teammate Andrew Jordan brought up the top five, while Mat Jackson posted the best finish of Motorbase's return round in BTCC with sixth place.
Colin Turkington, winner of the two earlier Snetterton races, had to do with seventh, while Rob Austin, Tom Ingram and Rob Collard made up the top 10.
Matt Neal, who started at the back after a black and orange flag in race two, fought his way up to 11th place.
His teammate Gordon Shedden, who had led the points heading into Snetterton, had another miserable race as he was forced to head to the pits due to car issues on lap three. He later rejoined and salvaged a point - just his third of the weekend - with the fastest lap of the race.
Plato's second-place finish allowed him to establish a 16 point lead over Turkington, with Shedden maintaining third in the standings and Tordoff moving up to fourth.
|23||Derek Palmer Jr.||Infiniti||1 Lap|
|24||Gordon Shedden||Honda||2 Laps|