Jordan Binnington made 33 saves for the Blues (24-19-8), who are 5-0-2 in their past seven games and lead the Los Angeles Kings by eight points for fourth place in the division.
"I thought that we [had a] lack of intensity in the second period for me more than anything," St. Louis coach Craig Berube said. "Not making hard plays, direct plays, not checking, just not being physical and hard to play against in the second period and just not very good execution with the puck tonight."
Anthony Stolarz made 24 saves and stopped all three shootout attempts for the Ducks (17-30-7), who split the two-game set following a 3-1 loss here Monday.
"Our guys came to play," Anaheim coach Dallas Eakins said. "We were able to skate and compete against a very good, very structured team. The guys were real upbeat on the bench, really supporting each other, and they obviously got the outcome that we want."
Ducks forward David Backes was given a standing ovation and video tribute during the first period, and the Blues stayed on the ice after the game to congratulate their former captain, who said this season, his 15th in the NHL, could be his last.
Backes, who was selected by the Blues in the second round (No. 62) of the 2003 NHL Draft and played his first 10 seasons for St. Louis, hugged some of his former teammates, including David Perron and Jaden Schwartz.
"I made it most of the way and then, you know, seeing the guys that I played with the longest really, really hit me in the heart, with 'Schwartzy' and all he's been through lately (Schwartz's father, Rick, died last November) and David Perron and how far he's come," Backes said. "It's just all the memories flood back of the great moments that we've had as friends and teammates.
"If you gave me a blank sheet of paper and said, 'How do you want to end your career?', this might have been second to, you know, hoisting the Stanley Cup and going out in that style. That's not always reality, so you know, this is pretty amazing."