Australian fly-half James O'Connor finished a jinking run with a try in the very last play of the first half, to narrow the scoreline to 19-10.
The Lions lead at the break thanks to Alex Corbisiero's early try, and 14 points from the boot of Leigh Halfpenny.
Australia could have been ahead, but turned down five opportunities to kick penalties for goal in the first period.
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Fine and sunny tomorrow morning with lots of sunshine to start the day. Feeling colder though, with maximum temperatures of 13°C.
Kathryn Tresilian reports from the town where the body of a 47-year-old woman was found dismembered in Pontypridd on Friday.
Some bright spells this afternoon, with outbreaks of rain. Top temperature 15°C.