Britain stayed close for the first seven minutes before Jackson took over.
With the game level at 11-11, she started an 18-0 run that blew the contest open. The 1.83-meter (6-foot-5) star, who carried the Australian flag at the opening ceremony, scored the first eight points of the spurt — hitting a 3-pointer, a jumper and converting a three-point play.
Julie Page finally ended Britain's 8 1/2-minute drought with a lay-in that cut the deficit to 18 points. Britain could only get within 11 the rest of the way.
Rachael Vanderwal scored all 11 of her points in the second half to lead Britain.