SYDNEY (Reuters) - After a five-year stint away playing 15-man rugby, World Cup winner and sometime heavyweight boxer Sonny Bill Williams returned to the sport where it all began for him in a blockbuster rugby league match on Thursday.

The 27-year-old former All Blacks centre, who has had six professional boxing fights, helped to attract a bumper crowd of 35,952 to the Sydney Football Stadium for his Sydney Roosters debut against the South Sydney Rabbitohs in the opening match of the National Rugby League (NRL) season.

It was not a winning start for Williams, though, and his try five minutes from time was little more than a consolation as the Rabbitohs, part-owned by Hollywood actor Russell Crowe, ran out convincing 28-10 winners.