Having already been eliminated from playoffs contention, the Blues took advantage of the second-placed Detroit having to use backup goaltenders as both Jimmy Howard (shoulder) and Chris Osgood (hernia) are sidelined with injuries.
St. Louis goaltender Jaroslav Halak made 41 saves and watched as his offense scored a season-high 10 goals.
"Thank God it's over," Red Wings coach Mike Babcock said. "Obviously we'll have to look at ourselves and do a much better job, because this was unacceptable."
Chris Stewart, Cam Janssen and Chris Porter all scored in the first period where St Louis (35-32-10) took a 3-2 lead before adding five more goals in the second.
Porter, whose first-period goal was his first of the season, added a second goal late in the third where Patrik Berglund also scored.
"We just kept pushing and it started steamrolling," Janssen said.
The Red Wings (44-23-10) have lost five of six games and have just a one-point lead over the San Jose Sharks for second place in the Western Conference.
Goaltender Joey MacDonald, who made 38 saves against the Chicago Blackhawks on Monday, allowed seven goals while his backup Thomas McCollum gave up three on eight shots.
Mike Modano gave Detroit a 1-0 lead 5:51 into the game while Todd Bertuzzi and Henrik Zetterberg also scored for the home team who had not conceded 10 goals in a game since 1993.