Prop Alex Corbisiero touched down after just two minutes, to put the Lions ahead against Australia in the series decider.
Full-back Leigh Halfpenny kicked the conversion from in front of the posts, to put the Lions 7-0 ahead.
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A group of ex-servicemen have become the first people to climb Pen y Fan in the Brecon Beacons for 24 hours non-stop.
Thousands of athletes are in Tenby for the competition which consists of a two mile swim, a 112 mile cycle ride and a marathon.