Medal favourites off to impressive start - London 2012 - Football
Medal contenders Brazil, USA and Japan kicked off the women's Football competition with victories on the opening day of action at London 2012.
Early goals from Francielle and Renata Costa put the Samba Queens in control, before captain Marta with a brace and substitute Cristiane sealed victory.
Abby Wambach and Carli Lloyd were also on target for USA after Gaetane Thiney and Marie-Laure Delie had given France a two-goal lead.
Japan established a two-goal advantage at the break, with the lively Nahomi Kawasumi and Aya Miyama both on target.
The Canadians restored their hopes with a strike from Melissa Tancredi after 55 minutes but could not find an equaliser.
Houghton kept her nerve with a 25-yard free-kick in the 64th minute, curling her effort expertly into the bottom corner.
Skipper Nilla Fischer, Lisa Dahlkvist and Lotta Schelin eased Sweden into a 3-0 lead before Portia Modise reduced the arrears with a spectacular long-range chip.
But Schelin restored the three-goal advantage, converting a near-post cross from Dahlkvist for her second goal.