Brazil began their hunt for Olympic gold with a 5-0 thrashing of lightweight first-timers Cameroon in Cardiff on Wednesday.

Three of the Brazilians' five goals came via set-pieces in a Group E opener that lacked a true competitive edge. Even so, Brazil have sent out a warning to the competing field, winning by a lopsided score despite failing to hit the high notes they're capable of.

The South Americans began the game with a defined sense of purpose, putting pressure on the Africans from the outset. They had their first goal after only six minutes, when Francielle stepped up and slammed a low free-kick into to the corner of the net. It was 2-0 just three minutes later, and once again Francielle was involved. She crossed a corner to Renata Costa, who made no mistake with a cool finish at the back post.

Five-time FIFA World Player of the Year, Marta, had trouble getting involved in the game in the opening period. But with precious little on offer from Cameroon, it hardly mattered for the South American qualifying champions, who have won silver at the last two Olympic tournaments.

The early portion of the second half lacked a spark as Brazil were happy enough to move the ball around the pitch and make the Africans chase. Marta, who found herself dropping back into midfield to get a sniff of the ball, finally got her breakthrough in the 72nd minute. Darting into the penalty area to collect a low cross from the right, she was hauled down unceremoniously and awarded a spot-kick. She duly finished it with aplomb.

Eight minutes later, the Brazilians finally found their true rhythm. Marta slipped an elegant through-ball to Cristiane, who rounded the keeper and poked home a cheeky goal from an acute angle. The two combined again to add a fifth and final goal three minutes from time. Cristiane rounded the keeper once more and crossed for Marta, who hit the ball into the open goal.

Brazil move to the top of the section with the victory, and they will next meet New Zealand on 28 July, while Cameroon face another heavy task against hosts Great Britain.