The 27-year-old, who finished third in Friday's super-G in the Italian Dolomites, finally mastered the tricky Saslong piste which had previously eluded him.
"It was one of my best downhills," said Odermatt, who celebrated wildly at the finish line after beating compatriot Franjo von Allmen by 0.45 seconds with American Ryan Cochran-Siegle just one hundredth of a second further back.
"If you want to win a downhill you need a perfect run," said Odermatt.
"Today, already on the top, which is not really my section, I could ski really well. Finally I also jumped well, and then it was really perfect, I'm really happy."
It was a 40th World Cup victory and the third of the winter for the defending downhill and overall champion after his successes in the super-G at Beaver Creek, Colorado and the giant slalom at Val d'Isere, France.
He matched the record of compatriot Pirmin Zurbriggen but is still far behind Swedish great Ingemar Stenmark's men's record of 86 World Cup wins in the 1970s and 1980s.
Odermatt's closest rivals could not match his speed with France's Cyprien Sarrazin and Austrian Vincent Kriechmayr having poor starts and Italian Mattia Casse, winner of Friday's super-G, labouring on key sections.
"I am very happy with it, I was not expecting such a good race," said 23-year-old Von Allmen whose only other World Cup podium came last year when he took third in the super-G at Garmisch-Partenkirchen.
"We have an amazing team, a very young team but already so fast," added Odermatt of Von Allmen. "We are doing well and the young guns are coming, that’s cool to see."
Cochran-Siegle claimed his third podium, all in Italy, after winning the super-G in Bormio in December 2020, and finishing third in the Val Gardena downhill the same season.
Odermatt moves to the top of the overall World Cup standings with 440 points -- 50 points ahead of Norwegian Henrik Kristoffersen.
He leads fellow Swiss racers Justin Murisier and Von Allmen in the discipline standings after the second downhill race of the season.
Kristoffersen, a specialist in technical disciplines, will be competing in the giant slalom and slalom races on Sunday and Monday respectively in Alta Badia, also in Italy.
