The Russians had an emergency hearing scheduled in Lausanne for 2pm (1300 GMT/9pm), two hours after the opening ceremonies kicked off in South Korea.
It's because they're competing as an "Olympic Athlete From Russia" as a result of punishment for doping offenses by the Russians in the 2014 Olympics.
In December, the International Olympic Committee banned 43 Russian athletes for life from the Olympics, but CAS overturned the suspensions of 28 athletes and partially upheld 11 other appeals - decisions International Olympic Committee president Thomas Bach described as "extremely disappointing and surprising" last Sunday.
CAS said the Russian side "did not demonstrate" that the process the International Olympic Committee put into place, two special panels to vet and independently review each individual application, was "carried out in a discriminatory, arbitrary or unfair manner".
South Korea-born Ahn is the most decorated short-track speedskater in Olympic history with six gold medals.
"The Olympic Athletes from Russian Federation obviously were a major focus for both the pre-Games taskforce and now at the Games".
Never mind that 45 Russian athletes were excluded from the games early Friday. Russia's flag will not fly at the Olympics, and its anthem will not be played at any medal ceremonies.
WADA's headquarters were illuminated in the colors of the Russian flag and showed words of support for Russian athletes who have been accused of doping violations.
Athletes from Russian Federation looked a bit muted compared to their fellow Olympians and walked in with an Olympic flag instead of that of their country during the opening ceremony on Friday - but it wasn't because of a fashion statement.
"We regret this. We are taking this decision into consideration. and undoubtedly we will continue to help athletes to stand up for their rights", Russian President Vladimir Putin's spokesman Dmitry Peskov told journalists.
Budgett promised there would be no repeat in Pyeongchang, where the laboratory is under round-the-clock video surveillance and will be monitored by experts from the World Anti-Doping Agency and the IOC.
IOC president Thomas Bach this week signalled he may be open to ending Russia's ban when he said the Olympic body wants them to observe the "letter and the spirit" of the conditions. Coaches and athletes have been playing on an uneven field.
"It's reassuring the IOC's decision has been upheld and we can get on with the Games and forget about doping".
It refused to invite some Russians even after their disqualifications from the 2014 Olympics were lifted by CAS last week.
With flags, patriotic tunes and a troupe of cheerleaders, Russian Federation wants to throw the biggest party at the Pyeongchang Olympics.
The IOC pointed to a CAS statement that declared the Russians were not necessarily innocent of doping, just that the evidence was insufficient to ban them.
"That is great news", said USA women's skeleton athlete Katie Uhlaender, who placed fourth in the Sochi Olympics - one spot behind bronze medalist Elena Nikitina, who was one of the 45 appealing her ban.
USA bobsledder Nick Cunningham said "If dirty athletes are taken out, then clean athletes will prevail".