Halfpenny kicked another nerveless three points, after the Lions earned a further penalty at the scrum.
When the Australian forwards couldn't live with the Lions at scrum time yet again, prop Ben Alexander was sent to the sin bin.
Halfpenny again made no mistake, to extend the Lions' lead to 19-3 after 26 minutes.
More top news
A father-of-two was murdered by three men in a vicious attack as a result of a drugs turf war, a court has heard.
Plaid Cymru kicked off its election campaign today with leader Leanne Wood vowing to defend Wales in Brexit negotiations.
The Tour of Britain is returning to Wales and it is finishing in Cardiff for the first time ever.