Aerni, who was only confirmed as the final member of the host nation's team last night, finished in 30th place in the opening downhill leg.

This made him the first starter for the conclusive slalom run.

The 23-year-old, who had never won a World Championship medal until today, produced a sizzling time of 44.47sec for an overall clocking of 2min 26.33sec.

Skier after skier proved unable to match it.

It marked the second successive World Championships Alpine combined event at which the eventual winner had started the slalom in 30th place.

Austria's Marcel Hirscher, the winner two years ago in Beaver Creek, duly finished second today just one hundredth behind.

"I was really nervous the last 45 minutes waiting for everyone to finish," said Aerni. 

"I could only watch and hope as the others came down. 

"I knew my slalom run was good, but with the combined you never know what will happen. 

"It was definitely a long wait until I realised I had the gold medal."

Swiss success continued with bronze for Mauro Caviezel, 0.06 off the pace.

Hirscher was 28th after the downhill and Caviezel was 14th as slalom specialists dominated.

Swiss skiers have now won three of the six gold medals claimed in St Moritz so far after Beat Feuz won the men's downhill and Wendy Holdener triumphed in the women's Alpine combined.

Tomorrow will see the Nations Team Event take place, an event due to make its debut on the Olympic programme at next year's Games in Pyeongchang.