Hirscher said he was relieved after leading Kristoffersen by 0.07 seconds in the first run.
“No matter what happens next, it’s great and super to know that I am among the fastest,” he said in-between the runs.
Clement Noel came closest, trailing by 0.38 in third, but the Frenchman skied out at a tricky passage close to the finish of the final run.
Many racers struggled at that point, and Hirscher said he was helped by teammate Michael Matt, who warned him over the team radio right after his run.
“Otherwise I could have easily lost those nine hundredths there,” said Hirscher, who added 0.02 to his first-run lead over Kristoffersen.
Hirscher and Matt were two of five Austrians in the top 10, and Hirscher expected some of them to close the gap to him and Kristoffersen soon.
“There has been a generation change in the slalom team, and those guys are now definitely ready for podiums and victories,” Hirscher said.
By coming runner-up, Kristoffersen kept a remarkable series going. Since the start of last season, the Norwegian has been on the podium of all 10 slalom races. Only Swedish great Ingemar Stenmark had more top-three slalom finishes in a row — 12, in 1975-76 and again 1977-78.
Sunday’s race was the first of the men’s season after a giant slalom in Soelden, Austria, was called off due to bad weather in October.
Last year’s winner, Felix Neureuther of Germany, skipped the race after breaking his right thumb in training Friday. Neureuther, who was set to make his comeback from a one-year break due to a torn ACL, flew back to Munich to undergo surgery.
The men’s World Cup continues with speed races in Lake Louise, Alberta, next weekend.