Perpignan's Hook notched 20 points, including a fine second-half try which restored parity at 21-21 before Wales edged home to a 30-21 victory.
Wales, who won their third Six Nations Grand Slam in eight years this spring, went into a 13-0 lead through Harry Robinson's try and Hook's kicks, but the Baa-Baas led 14-13 at the break after tries from Stephen Donald and Richie Rees.
Kiwi World Cup winning fly-half Donald then went over for his second try to extend the visitors lead before Hook rounded off a excellent worked score in the corner before effortlessly adding the extras.
Shane Williams did his best to continue his habit of scoring at the death in swansong matches but when he chanced his arm in injury time, Aled Brew intercepted and raced under the posts to rubber-stamp Wales' win.
It was a second-string XV for Wales, with a 16-strong party already in Australia preparing for the series, but another 18 will join them imminently, with Hook looking to force his way into Warren Gatland's thoughts.
63x46.png){kind=logo}