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
Wales' hopes of qualifying for the 2018 World Cup took a dent following a goalless draw with the Republic of Ireland in Dublin.
Clear skies overnight will set us up for a beautiful weekend with sunshine and lovely temperatures.
Shopping trolleys to be left unlocked as supermarket upgrades for new £1 coin.