The 24-year-old was only fourth-fastest in the downhill leg of the men's team combined down a Stelvio course on which he roared to victory in the individual downhill on Saturday.
All he could do then was sit back and hope teammate Tanguy Nef could pull out something special in the slalom leg later.
The unheralded 29-year-old Nef, who has never won a World Cup slalom, obliged in stunning fashion, weaving slickly through the 67 turning gates to set a combined target time of 2:44.04 that proved beyond anyone else.
Von Allmen and Nef ended up winning by a commanding 0.99 seconds, leaving Switzerland's top-ranked pair, Marco Odermatt and Loic Meillard, to share the silver medals withthe Austrian duo Vincent Kriechmayr and a charging Manuel Feller.
"The first one was on my own, still special, but this is even a little bit more special because I wouldn't have made it on my own today," Von Allmen told Reuters.
"I can really say thank you to Tanguy. He made the difference today. I had a really (weak) knees down here in the finish. I definitely ski better than I watch races, I think.
"Tanguy nailed it today."
Nef's previous claim to fame was a silver medal at the 2025 world championships alongside Alexis Monney when the new team combined event featuring one run in each discipline skied by two different skiers was rolled out, and the Swiss swept the podium.
Paired this time with Von Allmen, he went one better.
"It felt really good. I knew I had a lot of speed and was, 'OK, now just bring it home'. That's what happened," he said.
There was despair, though, for Italians Giovanni Franzoni and Alex Vinatzer.
Franzoni, who took the silver medal behind von Allmen on Saturday, was fastest in the downhill leg by 0.17 seconds on a crisp and sunny morning in the Italian resort.
But Vinatzer, the last skier to go in the second leg, buckled under the pressure and was only 18th fastest in the slalom as they finished seventh overall.
"I was extremely nervous at the start; it was a very difficult situation for me," Vinatzer said.
"Giovanni delivered an outstanding run and deserved nothing less than a medal, and I really wanted to give it to him but couldn't hold it together."
Odermatt arrived in Bormio as leader of the Swiss team, the dominant force in the sport and tipped for multiple golds.
Instead, it is Von Allmen who has underlined why he is tipped as the future of Swiss speed skiing.
Odermatt surprisingly failed to make the podium in the downhill, but at least he avoided that fate on Monday, although it was a close shave with Austrians Raphael Haaser and Michael Matt missing a medal by 0.03 seconds in fourth place.
"First we were a little bit nervous it might be another fourth place," the 28-year-old Odermatt said.
"We already have our souvenir from the Olympics."
After Nef had blazed down in 51.82 seconds, the best slalom run, there were three skiers still to go.
But Meillard produced a disappointing run to the frustration of Odermatt, who was watching in the finish area.
Switzerland's third pair of Monney and Daniel Yule had been second after Monney's impressive downhill, but Yule could make no impression as they slipped back.
It was then left to Vinatzer to spark an Italian party, but he never looked comfortable under the spotlight as time and Italy's chances ebbed away.