Just four days after celebrating his 21st birthday, Johnstone recorded his first World Cup victory in 11 career starts, which elevates him to equal leader of this year's points table.
Although only two rounds of this year's World Cup have been completed, the win in China's north eastern Heilongjiang province in -20 C temperatures will enable Johnstone to mount a serious assault on this year's World Cup title, a feat that no other Australian has achieved.
Since finishing the 2008/2009 season as the number two ranked World Cup halfpipe rider, he has consistently shown that a World Cup title could soon be added to his already-impressive resume.
Johnstone's win in the Yabuli event, the first halfpipe World Cup event to be staged on Chinese soil, saw him finish ahead of China's Yiwei Zhang, with compatriot Wancheng Shi in third place.
The AIS/NSWIS scholarship holder was supremely dominant in his first run, finishing the first stage 5.5 points in front of the next best athlete, China's Wancheng Shi.
Johnstone, who was clearly the top qualifier earlier in the day, continued the form that captured his first World Championship title in Spain last month, by finishing with a resounding 27.6 points out of a possible 30 in his second and final run of the day.
A clean run of a frontside 900 mute to backside 900 melon, back-to-back 720s and a front side air put an end to the hopes of Johnstone's rivals.
In the women's event, Johnstone's teammate and fellow World Champion, Holly Crawford, was unable to repeat the form which enabled her to win in Spain last month, narrowly missing the podium in fourth place.