Brandon Hagel, Patrick Kane and Dominik Kubalik scored, and Alex DeBrincat had two assists for Chicago (15-18-5), which won its fourth straight game. Fleury got his third shutout of the season and his 70th in the NHL.
The winning streak began after the players held a meeting following their sixth straight loss, 6-4 at the Arizona Coyotes on Jan. 6.
"I think the thing I like about it," Blackhawks coach Derek King said, "and this is where you kind of get to know your team a little better, is when they do close that door and they have a chat and powwow, we know what's going on, but we (the coaches) don't know what's being said. The fact they acknowledged something had to be said or done about it, that's great. That means they're a team, and supporting each other to go on a winning streak here is a bonus."
Lukas Dostal made 33 saves in his second NHL start for Anaheim (19-15-7), which has lost three in a row and eight of 10.
"Hey, I thought he did his job," Ducks coach Dallas Eakins said of Dostal. "That first goal was a crazy one. The puck comes out and it's kind of too far out for him to grab it. The guy comes out of the box. People who say there's no luck in the game are crazy. There's a fair amount of luck that goes with it. He made some good saves along the way. I thought he was solid. I thought he gave us a real, real solid game."
Hagel made it 1-0 on a 2-on-1 at 5:33 of the second period when he took a pass in the slot from Erik Gustafsson, who had come out of the penalty box 10 seconds earlier. Gustafsson chased down Riley Stillman's pass in the left corner of the offensive zone moments after Jakub Galvas cleared the puck off the goal line for Chicago and Fleury stopped Derek Grant in close.