The InBev lower-alcohol lager, which was only launched last August, fought off competition from Cadbury's Creme Egg Twisted and Birds Eye Arctic Roll to take the title, having racked up sales of £29.9m in the year to 21 March 2009.
The brand's success had exceeded InBev's expectations, said the company's UK marketing director, Andreas Hilger.
"Stella Artois 4% has performed exceptionally well, with an especially strong sales performance in the take-home sector, making it one of the most successful beer launches of the last decade," he said.
The brand's multimillion-pound marketing campaign had played a large part in the launch's success, helping rid the parent brand of its 'wifebeater' image, he added.
"We have created a new world for Stella Artois 4%, set in the classic 1960s Continental Riviera. This has helped us capture the wry sense of humour and strong cinematic look that has always been at the heart of the Stella brand," Hilger said. He revealed that further "innovative marketing" would support the brand over the next year.
Joe Hale, brand analyst at Dragon Range, said the figures marked an overdue success for Stella Artois.
"The brand's image had been tarnished and needed new life and direction," Hale said. "Drinkers needed to be told why Stella was the right choice for lager drinkers.
"Whether 4% will be able to do enough to completely shed the 'wife-beater' tag remains to be seen, but its success to date might just project a much-needed halo effect on the parent brand."
Hilger claimed the brand had become an ambassador for the premium lager category. "Our industry is operating in challenging market conditions, but this success has shown there is a demand from consumers looking for an innovative, premium 4% beer that doesn't sacrifice quality."
Quarterly results from InBev this month showed improved market share for Stella Artois, although its UK volume sales slumped 6.8%.