It was the 19th podium-topping performance of Pinturault's career, but after holding a big advantage after the first leg on the Chuenisbargli piste, was relieved to close out his victory.
World Cup overall leader Hirscher was claiming his 100th podium, a mark only surpassed by the great Ingemar Stenmark (155) and was mighty close to adding another win.
But Pinturault held on by four-hundredths of a second to make his own piece of history.
"I thought when I crossed the line it was long enough for me," he admitted.
"One or two more gates and I would maybe have been behind, but its a very special victory," he told the official FIS website.
Another Austrian, Philipp Schoerghofer, joined Hirscher in the top-three.
Hirscher was still delighted by his performance.
"I'm super, super happy with my second run and it's another 80 points in the books," he said.
Killy, who was the star of the first World Cup season back in 1967, went on to win three gold medals at the 1968 Grenoble Olympics before retiring at the end of that year with a remarkable record.
The 25-year-old Pinturault made his World Cup debut as a junior in 2009 and has bronze medals in giant slalom at the 2014 Sochi Olympics and 2015 world championships at Beaver Creek.
Worley wins as Maze says farewell
In the women's giant slalom event at Maribor in Slovenia Saturday, Tessa Worley made it a double success for France with a notable victory as home skier Tina Maze bade an emotional farewell to the circuit.
Worley held off Italy's Sofia Goggia with Switzerland's Lara Gut in third place.
Overall World Cup leader Mikaela Shiffrin finished fourth and has a 205-point lead in the standings ahead of Gut.
Worley, who was claiming her 11th GS win, leads the discipline standings after the victory.
"It's intense but it's awesome," she said.
Maze officially brought down the curtain on her 18-year career which has seen her win two Olympic golds and four world championship titles.
She stopped halfway down the first run to greet her partner and a former coach before taking off her skis to cross the line on foot to a rapturous reception from the home crowd.
It meant a DNF and not classified in the official results but it did not matter.