Vonn's victory in the super-G event at Garmisch-Partenkirchen in Germany gave her the outright lead in the speed discipline ahead of this month's finals in France.
Having finished seventh in Saturday's downhill, the 30-year-old rebounded by coming home 0.2 seconds ahead of overall World Cup leader Tina Maze, whose coach set up the course.
It put Vonn eight points ahead of super-G world champion Anna Fenninger, who placed third to give back the 20 points she'd earned over Maze the day before -- when their positions were reversed.
"I think it was set probably against Anna," said Vonn, who took bronze behind Maze at last month's world championships in Colorado
. "That was a wise choice by Tina's coach. But it also really suited me and I liked it."
"It's going to be a close fight in downhill and super-G, so I will really have to ski my best at the finals in Meribel. Hopefully I can get two titles," added Vonn, who is 35 points ahead of Fenninger in the downhill standings.
But Vonn is well off the pace in the fight for the overall crown -- which she last won in 2012, her fourth success -- in third place almost 200 points behind the Austrian.
Maze is another 44 points ahead of Fenninger, with just two slalom events in Sweden next week before the March 16-22 finale.
"Of course it's a great result but I prefer to win," the Slovenian said. "Lindsey was simply better today and she deserves this win.
"My whole team stands behind me and supports me and I am really thankful to them. Valerio did a great job setting the course. It was a fast and nice course set with not too many turns."
Fenninger, who also won the world giant slalom title at Beaver Creek, said she will focus on her strengths after claiming a 12th podium this season.
"It was a fast super-G and that's maybe not what I am the best at," said the 25-year-old.
"Overall it's been a good weekend. Honestly I thought Tina was going to be better than me in the downhill and that I would catch up in the super-G. It turned out to be different.
"I am focusing on my strengths, this is why I am not going to race slalom next week. Now I have to train giant slalom in order to show my best skiing and maximize my chances to win the giant slalom globe."
Meanwhile, Kjetil Jansrud clinched the men's Super-G title with victory on home snow in in Kvitfjell on Sunday.
The Norwegian, who missed out on securing the downhill crystal globe when he finished seventh on Saturday, opened up an unassailable 123-point lead over Italian Dominik Paris.
"This is the first globe of my career," said the 29-year-old. "It's good to not have to go into the final weekend feeling like there are two guys pushing me on the cup and I have to fend off both of them. That's a big thing because I can leave the super-G and focus on the downhill."
Jansrud has a 20-point lead over Hannes Reichelt in the downhill, but is less confident of overhauling his 52-point deficit on another Austrian, three-time defending champion Marcel Hirscher, in the overall standings.
The men next travel to Slovenia for slalom events next weekend.
"I think he will gain some extra points in Kranjska Gora, so I'm not very concerned about the overall," Jansrud said of Hirscher.
"I think he'll pull through. But it might get exciting. He has no room for error and anything can happen."