St-Germain shocks Shiffrin for world slalom gold at Meribel
It meant the end of Shiffrin's bid for a fifth world slalom title after she dominated the first of two runs in the French resort, but floundered on the second to allow the Canadian in for a stunning victory.
The result still saw the 27-year-old American leave the champs with giant slalom gold and a second silver from the super-G.
St-Germain had been third fastest after the first leg down the Roc de Fer slope in sunny, warm conditions and held her nerve on the second run for a winning aggregate time of 1min 43.15sec.
It was a remarkable victory for the 28-year-old Quebec native who has never made a World Cup podium. The best result of her 13 top 10 finishes from her eight seasons on the circuit is a fifth place in a parallel slalom in St Moritz in December 2019.
"That is weird!" St-Germain said when asked how it felt to be the newly-crowned world champion.
"I was really not expecting this obviously. I was really stressed, I was kind of nauseous.
"I had bit of a mistake but I was thinking 'go down, go down, go down', and it worked out."
Shiffrin, whose attention will immediately turn to her bid to equal and then surpass Ingemar Stenmark's overall record of 86 World Cup victories, suffered a terrible second run to finish 0.57sec off the Canadian's pace, with Germany's Lena Duerr taking bronze (+0.69).
Italy's Lara Della Mea took up the early lead in the second leg, with a third of the course in the shade and course workers battling rapidly melting snow under the bright sun.
That held through 15 racers until first Sweden's reigning Olympic giant slalom champion Sara Hector and then Norway's Mina Fuerst Holtmann went atop the leaderboard.
The top eight readied themselves for their second descent, Sweden's Hanna Aronsson Elfman failing to bother the podium, while Croatian teenager Zrinka Ljutic disappointingly skied out and Slovenia's Ana Bucik came in just behind Della Mea.
The business end of the day's racing saw Slovakia's reigning Olympic champion Petra Vlhova, fifth fastest in the first leg, go second 0.14sec behind Holtmann.
Germany's Duerr then nipped in ahead of the Norwegian, piling the pressure on the top three.
First down was St-Germain, who not only refused to buckle but took the lead by 0.69sec in a swashbuckling display of aggressive slalom skiing.
Switzerland's two-time Olympic slalom medallist Wendy Holdener looked prime to go top, but skied out with the line in view.
That left Shiffrin in the starthut, but a hesitant start saw the American lose time throughout, eventually clocking the 27th slowest time of the top 30 to finish second.
The silver sees Shiffrin move clear of former Swedish racer Anja Paerson to a personal tally of 14 world medals. Only Germany's Christl Cranz (15) has more, but she was skiing between 1934-39, when world champs were held every year and ski racing was yet to evolve to what it is nowadays.
Having also won slalom bronze in the 2021 worlds, Saturday's silver also saw Shiffrin become the first skier, male or female, to claim at least six world championships medals in a specific event.
