For the second night in a row, Lauren Jackson did her country's heavy lifting at the Olympic Games.

After starring in the Opals' 74-58 win over Great Britain to start their Games campaign, the Australian flagbearer admitted combining "the greatest honour of my life" with her day job as the women's basketball talisman had take an emotional toll.

"I'm beat," said Jackson, close to tears after a game-high 18 points and five rebounds in just 20 minutes of court time.

"I'm just ready to go to bed. It's been an emotional 48 hours."

Jackson may have been tired and emotional after leading the Australian Olympic team at the opening ceremony, and as coach Carrie Graf said afterwards, playing on fatigued legs and fumes.

But it didn't stop the 31-year-old Opals skipper from being brilliant to open her fourth Olympics campaign.

Her combination of cool head and hot hand helped the Aussies overcome some early sloppiness to see off a spirited world No.49, coached by Australian Tom Maher.

Jackson's points came mostly at crucial times to keep the Opals from paying more dearly for a sluggish start.

Great Britain could have been in front at quarter-time as the Opals struggled for rhythm and dangerous Liz Cambage found herself in early foul trouble.

The Britons had more first quarter shots than the Opals but posted ugly shooting numbers - an abysmal 19 per cent from the field for the term.

An 18-0 run to start the second quarter sparked by Jackson and tighter defence provided the buffer for the victory.

It also took out of play any prospect of a lift from the noisy home crowd in the cavernous basketball arena as the Opals led 39-25 at halftime, and maintained their lead in double-digits throughout.

Graf had to manage the win without big minutes from Cambage and the important Jenna O'Hea, who both had three fouls clocked up soon after quarter-time.

But despite Jackson's physical tangle with Great Britain's Julie Page moving her to a fourth foul and the bench early in the final term, the Opals kept their buffer.

Australia's main rivals in London - the United States - earlier beat Croatia 81-56 to begin their gold medal defence in Group A.

The victory stretches their Olympic winning streak to 34 games.