The 29-year-old —- a four-time World Cup giant slalom series champion — timed two minutes 38.75 seconds to beat Austrian ace Marcel Hirscher with Frenchman Alexis Pinturault third.
Norwegian Aksel Lund Svindal failed to finish and also lost his lead in the overall World Cup standings as Hirscher's runners-up spot saw him overturn the deficit and take a 58-point lead.
Ligety, who has yet to win the giant slalom Olympic crown though he won the combined Olympic gold in 2006, built an impressive lead after the first run of more than a second over both Hirscher and Pinturault, who had won the men's super combined last Sunday.
Ligety's second run went without any major scares to see him to his 21st World Cup victory, all bar one — the super combined in Wengen in January — in the giant slalom.
"In training I could sense that I was quick," said Ligety.
"My skiing is in the right place and it is good to win here before the Games."
Ligety's return to form — he failed to finish in both Adelboden and Val d'Isère in January's races — reinforces his status as favourite for the Olympic race which is programmed for February 19th.
"It is great to rediscover my best form at this particular time," said
"Things are coming together," he said.
"The Sochi course is not that different from Beaver Creek or here (Saintt Moritz).
"The mountain there will suit my skiing."
The Games get underway in the Russian Black Sea resort of Sochi next Friday and run till February 23rd.