It was a day of starkly contrasting fortunes for the two figureheads of the U.S. ski team.
The 23-year-old Shiffrin had just put down what turned out to be the winning run, edging out Italian Sofia Goggia by 0.02 seconds, and was watching the screens in the finish area as speed queen Vonn started.
Former Olympic champion Vonn, winner of 82 World Cup races, began well but lost her line as she approached a small jump and hit a marker gate, before careering across the slope at high speed and into the safety netting.
Shiffrin could hardly bring herself to watch as Vonn was attended to by course officials and medics, but thankfully the 34-year-old got back on her skis and made her way to the bottom.
She waved to the crowd and received warm applause.
“I feel like I’ve been hit by an 18-wheeler,” Vonn told a news conference later. “I got the wind knocked out of me but it’s okay. I wasn’t expecting it. I’ll have to watch the video.”
The technical layout caused problems for many, but Shiffrin, who already has 56 World Cup wins including 13 this season, found the balance between speed and control to power to gold.
It was her fourth world title but the first three had all been in slalom, the event in which she is almost untouchable.
Swiss Corinne Suter was third, 0.05 slower than Shiffrin.
Only 0.54 seconds separated the top 10 finishers.
“This is crazy,” she said. “It was a really tight race, the differences were like nothing. It was a fight. It’s tough, all these girls deserved to win.”
Two-time world champion Vonn, who has struggled with knee injuries throughout her career, has said she is retiring after the championships in the Swedish resort.
She could still end her career in fairytale fashion, however, with the downhill still to come, provided she suffered no damage during her spill on Tuesday.
Despite the Super-G course being slightly shortened, it still proved a formidable piste with several skiers going off. Another American, Laurenne Ross, also crashed heavily as the cloud cover came down to create tricky light conditions.
Czech Ester Ledecka, surprise gold-medallist in Super-G at last year’s Winter Olympics, finished outside the top 20.