Germany's Laura Dahlmeier came in first in Saturday's race, which combines cross-country skiing and rifle shooting, with a finish time of 21:06.2 and no missed shots.
Dahlmeier won five gold medals at last year's IBU World Championships but finally got her hands on a previously-elusive Olympic title to begin her Pyeongchang 2018 campaign in ominous fashion.
Ukrainian Valentina Semerenko was 46th, Anastasiya Merkushyna was 55th and Iryna Varvynets - 73rd.
Clare Egan (Cape Elizabeth, Maine) narrowly missed the cut in 61st place with three penalties, while Susan Dunklee (Barton, Vermont) was 66th and Joanne Reid (Palo Alto, California) finished 86th.
"Theoretically I could (qualify)", she said, "but I'd have to have a really, really good individual race". "Kind of a nightmare but weird things happen in big races I guess".
Egan had one penalty in prone and another in standing after a problem with her rifle. "Then I misfired, my bullet didn't eject and I wish I had refocused better after that". Dunklee took silver in the 12.5km mass start. It was the first time a US woman had won a medal at worlds.
On the bright side, there was her cheering section, which included her mother Beth Heiden Reid, a 1980 Olympic bronze medalist in speedskating.
Impressive Ireland thrash Italy in Dublin
Of course, the negatives at the tail end are all out-weighed by a comprehensive win brought about by Ireland's insistance on dominating possession and running from deep.
As if the biathlon - a sport that mixes the endurance and speed of cross-country skiing with the focus and precision of shooting a rifle - isn't already hard enough, it just got tougher. Biathletes at the PyeongChang Games will have additional challenges to contend with over the next two weeks at the Winter Games, including shooting under floodlights at night when temperatures are colder and the wind gustier.
That means bitter cold, wind and artificial light. Unlike some other Olympic events in Pyeongchang, there is no net set up to stop it.
World Cup holder proved far too strong for the rest of the field as she produced a near-perfect performance to clinch the first gold medal in the sport at the Winter Olympic Games here.
Dunklee, who won gold and silver at the world championships past year to put herself in position to contend for an Olympic medal, missed five targets and finished a distant 66th.
Silver medalist Marte Olsbu of Norway called the course "difficult" because of the wind on the shooting range.
Also on the U.S. team is Emily Dreissigacker, the daughter of U.S. Olympic rowers Dick Dreissigacker and Judy Greer.