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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Welcome to the Newsweek Quiz - where we'll be testing your knowledge from the last seven days of news here in Wales.
Ospreys lock Lloyd Peers has joked that a change of name after marrying his wife, could mean better fortunes on the pitch.
Much of Wales is bathed in warm sunshine at the moment, but be warned! It is about to come to an abrupt end overnight!