The Swiss, who was outpaced by his team-mate, Jason Plato, in Sunday's qualifying sessions, was never headed in his Williams-run Renault-Laguna and jumped into an immediate championship lead.
Electrifying starts ensured that Menu was ahead of the pack by the time the world's top touring car racers reached Donington's first corner. Such was his dominance that he was able to back off and cruise to the finish of the second race.
"The team told me to take it easy and to me easy means backing off a lot," Menu said later with a smile.
Plato gave chase to his more experienced partner in both races, finishing the day's opening round in second place. However, when he was well placed to repeat the result in the second race of the day, his Renault's engine overheated and forced him to retire. "I'm still happy though. Being fastest in qualifying gave me enormous confidence and I learned a hell of a lot," the 28-year-old said.
Plato's retirement from the second round ensured the champion, Frank Biela, of a podium place. His four-wheel drive Audi, forced to run 95kg heavier than its front-wheel drive rivals, had to give way to Rickard Rydell in the closing laps of round two, dropping to third behind the Swede's Volvo. "This result was better than I expected. I'm sure we'll improve but Menu already has a big lead in the title chase," the German said.
Both Biela and Volvo Rydell were forced out of the day's first race with damaged radiators, consequences of the close racing which brought over 30,000 spectators to the Leicestershire track. The second Volvo, driven by Kelvin Burt, was third in the opening round, just holding off David Leslie's Nissan, but gear selection problems dropped him to ninth in the day's other event.
The day could hardly have gone better for Menu. Apart from the mixed fortunes of Biela and Rydell, Gabriele Tarquini, the former BTCC champion, was only able to claim seventh and fourth place finishes. The Honda driver closed on Biela as the second race wound down but, as he explained afterwards, an accident in qualifying had turned his pace-setting car into a midfield runner.
His team-mate, James Thompson, proved much quicker but lost a wheel in the first race and was forced to fight back from a spin in race two. The Yorkshireman was lying second, just ahead of Plato, when the Renault driver tried to pass. Thompson spun off then staged a fightback to finish sixth.
In his charge, he passed Derek Warwick, the former grand prix driver who was making his debut in a Vauxhall run by his own team. Warwick brought his car home in the points in both races, while his team-mate and the 1995 champion, John Cleland, was out of luck, suffering clutch failure in the second race.
Scotland's Colin Gallie made an impressive debut, claiming victory in the Total Cup for Independents in his Pyramid Motorsports BMW320.
BRITISH TOURING CAR CHAMPIONSHIP (Donington Park): Round One (18 laps): 1 A Menu (Renault Laguna) 29min 36.77sec, ave speed 91.23mph; 2 J Plato (Renault Laguna) at 3.14sec; 3 K Burt (Volvo S40) at 24.24; 4 D Leslie (Nissan Primera) at 24.52; 5 J Bintcliffe (Audi A4) 30.54; 6 P Radisich (Ford Mondeo) 35.67; 7 G Tarquini (Honda Accord) at 38.83; 8 P Watts (Peugeot 406) at 39.18; 9 D Warwick (Vauxhall Vectra) at 39.35; 10 T Harvey (Peugeot 406) at 44.78.
Round Two (18 laps): 1 Menu 29min 49.84sec, ave speed 90.57mph; 2 R Rydell (Volvo S40) at 2.36sec; 3 F Biela (Audi A4) at 4.26; 4 Tarquini at 5.50; 5 Bintcliffe at 11.68; 6 J Thompson (Honda Accord) at 14.44; 7 Radisich at 20.24; 8 Warwick at 22.28; 9 Burt at 23.63; 10 C Gallie (Pyramid Motorsports BMW320) at 1:20.78.
Fastest Lap: Menu 1min 37.08secs, ave speed 92.70mph.
Championship standings: 1 Menu 30pts; 2 Plato 14; 3= Burt, Bintcliffe, Tarquini, Rydell 12; 7 Biela 10; 8 Radisich 9; 9 Leslie 8; 10= Thompson, Warwick 5.Reuse content