Brock McGinn scored, and John Gibson made 28 saves for the Ducks (10-12-3), who have lost five of seven (2-4-1).
"There were [scoring] chances, but ours were sporadic, and they were getting chances with sustained pressure and that was because we were late to pucks," Ducks coach Greg Cronin said. "We just didn't win enough puck battles and when they had the opportunity to shoot pucks through, they got them through. We had a really hard time getting pucks through."
Rossi gave the Wild a 1-0 lead with a power-play goal at 4:22 of the second period. Drew Helleson was in the penalty box for tripping when Kaprizov made a long backdoor pass to Rossi and he roofed the shot.
Rossi had moved into the top-line center position in place of Joel Eriksson Ek who was injured in the third period of a 3-2 overtime win against the Vancouver Canucks on Tuesday and was placed on injured reserve on Friday.
"Marco is a first-line center, there's no doubt about it," Boldy said. "So for him to step into that role is, I don't want to say it's easy, but he's used to it, he's been playing in that situation."