American Huckaby and France's Hernandez are the SB-LL1 Paralympic and world champion, respectively, but their involvement at these Games had been uncertain following the removal of the classification from the programme.

Both athletes had to receive an interim injunction from a German court to be permitted to compete in the SB-LL2 class, a verdict which International Paralympic Committee President Andrew Parsons admitted the organisation was "surprised and disappointed with".

Hernandez was quickest on both runs during qualification at the Zhangjiakou Genting Snow Park, and the top-ranked athlete with her second attempt of 1min 8.38sec.

Huckaby was left with work to do after a disqualification for straying off the course on her first run, but recovered to place second in 1:11.13.

SB-LL2 world champion Lisa Bunschoten of The Netherlands, a silver medallist in this event at Pyeongchang 2018, was third from her first run of 1:12.09, with Canada's Lisa DeJong - runner-up at the World Championships in Lillehammer in January - fourth with 1:12.22.

All 13 athletes progressed to tomorrow's competition, with qualification results used to determine the quarter-final line-up.

In the men's events, China's snowboarders excelled in SB-UL qualifying.

Zhu Yonggang climbed from eighth after his first run to top of the 18-man field with a superb time of 1:02.81, followed by Yang Jian in 1:03.03.

Wang Pengyao was third with a 1:03.12 effort, with Ji Lijia underlining the host nation's dominance by clocking 1:03.34.

American Michael Spivey and Matti Sairanen of Finland missed out on the top 16 and were eliminated, with a 1:09.73 second run from Lee Chung-min of South Korea keeping his hopes alive after he was slowest on the first.

World champion Tyler Turner of Canada impressed in the SB-LL1 preliminaries, with a second run of 1:04.24 representing a major improvement and sending him through as comfortably the best qualifier.

Wu Zhongwei of China was second with a 1:05.03 on his first run, with the defending champion Mike Schultz of the United States placing third despite a disqualification on his second run.

All 15 SB-LL1 competitors progressed to tomorrow's quarter-finals.

A significant marker was also laid down by Finland's Matti Suur-Hamari in the men's SB-LL2.

The world and Paralympic champion topped qualifying in 1:01.73, with the US' Garrett Geros his closest challenger in 1:02.46.

Canada's Alex Massie ranked third in 1:02.65, closely followed by Australia's Ben Tudhope, a silver medallist in this event at the World Championships.

Shinji Tabuchi of Japan was the last of the 16 athletes who progressed in 1:07.36, with Britain's Andy Macleod among the seven who missed out.

Snowboard cross medals are set to be decided tomorrow.