A place on the top of the podium instantly granted their country three spots, the maximum possible for a single nation, in the pairs competition at next February's Pyeongchang Games in South Korea.
Finishing any lower down the pecking order would have left China, which will host the 2022 Winter Olympics, with fewer spots in an Olympic competition featuring 20 couples.
That would have been a real blow to a nation that is desperately trying to boost interest in winter sports in the lead up to the Beijing Games.
A country that regularly finishes among the top three nations at a summer Olympics has discovered that it is much more difficult to nurture champions willing to try their luck on snow or ice.
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It was only 15 years ago when speedskater Yang Yang earned the world's most populous country their first gold medal at a Winter Olympics. It has been painfully slow going since then as that gold haul now stands at 12.
Figure skaters Shen Xue and Zhao Hongbo contributed to that tally when they won the pairs title at the 2010 Vancouver Games.
But with China having drawn a blank in figure skating four years later in Sochi, Sui and Han knew they had to improve on two successive silver-medals at the worlds if they were to secure more Olympic air time for their ambitious nation.
Forced to sit out the start of the season as Sui recovered from surgery on her right ankle and left foot, they utilised the time to plot their path to glory in Helsinki.
All that extra homework paid off on Thursday because even when Sui crashed to the ice following a mistimed landing in the side-by-side triple Salchows, she brushed off the mishap and powered to victory with Han.
After securing China's first world title since Pang Qing and Tong Jian won the same discipline in 2010, Han's thoughts immediately turned to what the victory meant for his country.
"We feel very lucky because the China will be hosting the 2022 Olympic Games, so all the people and the government give us a lot of support," said Han, who beat German duo Aliona Savchenko and Bruno Massot with a personal best total of 232.06 points.
"We want to be better and we want to be the best for ourselves and get ready mentally and physically so we can make the best performance for our country."
(Reporting by Pritha Sarkar; Editing by Alison Williams)
