By Patrick Lang
In the last race before the Vancouver Olympics, the American clocked one minute 1.77 seconds to grab her ninth overall victory of the season.
With only two races left this season Vonn leads Swiss Fabienne Suter by more than 200 points in the Super-G standings and cannot be caught.
Vonn also strengthened her overall World Cup lead over Saturday's downhill winner Maria Riesch who now trails her by 137 points. Her German friend and rival hit a gate and finished 11th.
"I saw that Maria had not been doing so well and I really went for the points. Luckily, there will be no points awarded at the Olympics. I will only think about victory," Vonn said.
"In a way, it was not so bad losing yesterday. I'd rather lose here and win in Vancouver."
"I saw the beginning of Roger's final in the start area and I saw he was taking a lot of risks. It gave me motivation to go for it today," added Vonn.
Austria's Andrea Fischbacher, who beat the American in Friday's Super-G leg of the super-combined on the same piste, and France's Marie Marchand-Arvier were joint second on the same time.
It was Marchand-Arvier's best World Cup result after two previous third places. She and Fischbacher were 0.17 seconds behind the winner.
The Frenchwoman, silver medallist behind Vonn at the world championships last year, is hitting form at the right time.
By contrast the Olympic hopes of Italy's Nadia Fanchini, the world championships bronze medallist, appeared to be shattered when she tumbled down the Corviglia piste and screamed in pain after hurting her knee.
The extent of her injury was not immediately known but she was taken away from the course on a stretcher.
Swede Anja Paerson, winner of Friday's super-combined, missed a gate at the same spot where Fanchini crashed and failed to finish.
(Editing by Justin Palmer)