The 20-year-old beat Swiss pair Marco Odermatt and first-run leader Gino Caviezel to take victory having never made the podium at a World Cup event before.
Norway's Lucas Braathen claimed his first World Cup victory in the Soelden giant slalom on Sunday (18 October).
The 20-year-old moved up from fifth on the first run to make his first trip to the podium a winning one in the opening race of the new alpine skiing season.
"First victory, first race of the season is unbelievable," an elated Braathen said afterwards, "Second run I went for it, I'm not here for fifth place, I want first."
Former multiple world junior champion Marco Odermatt was second, just 0.05s behind, with fellow Swiss Gino Caviezel third having held the lead after Run 1.
Disappointment too for Zan Kranjec who finished seventh after ending the first run in second place.
The women had to contend with snow and fog on their Run 1 yesterday morning, but blue skies and sunshine greeted the men today on the Rettenbach glacier.
After Run 1, just 0.15s covered the top four.
Giant slalom specialist Caviezel led the way with 1:08.13, 0.06s ahead of Slovenian Kranjec with Norwegian star Kristoffersen just one-tenth off the pace.
Pre-race favourite Pinturault was within touching distance too, the Frenchman fourth just 0.15s behind.
The weather was good but the course was unforgiving with reigning Crystal Globe holder Kilde losing a ski as he missed a gate.
The most consistent skier of last season was out.
But the order was shaken up drastically by the second run.
Odermaat produced a superb ski, moving up into a significant aggregate lead having been seventh on the first run.
The 22-year-old was soon overhauled by Braathen who was fifth after the first descent.
The youngster, who was sixth in this race 12 months ago, clocked the second fastest second run to pip Odermaat by just five-hundredths of a second.
Then the big names struggled with Pinturault and Kristoffersen failing to get close to Braathen's target.
The top two remained at the top of the timesheets with Caviezel, who had an advantage of 0.24s from Braathen on the first run, finishing 0.46s adrift.