DETROIT -- The St. Louis Blues took full advantage of a backup goalie and another netminder making his NHL debut.
"We just kept pushing and it started steamrolling," Janssen said.
The Red Wings gave up eight goals in the first two periods of a game for the first time since 1986 and 10 in a game for the first time since 1993.
"Thank God it's over," Detroit coach Mike Babcock said. "It looked like it was never going to end there for a while. It was unacceptable. Any way you look at it -- more than a touchdown -- it's ugly."
Joey MacDonald, playing for the injured Jimmy Howard, was chased after giving up five goals midway through the second period. MacDonald was back in net for the third period after Thomas McCollum, called up Monday from the East Coast Hockey League because Chris Osgood is also injured, gave up three goals on eight shots in a debut he would like to forget.
"Things can only go up from here," McCollum said.
Jaroslav Halak, meanwhile, made 41 saves for the Blues.
Detroit has won only one of six, cutting its cushion to six points ahead of Nashville in the Central Division with five games left for both teams and its lead over San Jose to a point in a race to be the second-seeded team in the Western Conference playoffs.
"We have to find ourself again," Henrik Zetterberg said.
Especially, in the Motor City.
Detroit is 10-12-4 at home after starting the season 10-1-2 at home in Joe Louis Arena.
"Definitely not good," Zetterberg said.
The Blues are out of the playoff race, but they're playing well enough to be in a 3-0-1 stretch that has put Columbus in last place in the division.
"The guys know how important it is to start creating success now," St. Louis coach Davis Payne said. "We could talk about what hasn't happened this season, but we're just focused on working to lay the groundwork for us down the road. Good habits aren't something you just turn on, you have to work to create them."
Detroit scored first on Mike Modano's slap shot off a rebound 5:51 into the game, then it went downhill for the home team that was jeered early and often by a sellout crowd.
"We got booed off the ice and rightfully so," Nicklas Lidstrom said. "We were just awful."
Chris Stewart started the scoring flurry at the 14:06 mark of the first period and Janssen ended a 114-game streak without a goal two minutes later.
"Unbelievable," Janssen said after scoring for the first time in two-plus years. "I'm going to my phone. I probably have about 500 text messages."
After Todd Bertuzzi made it 2-2 late in the first, Porter scored what the final go-ahead goal 29 seconds later.
Detroit didn't score again after Zetterberg's 24th goal of the season midway through the second period.
The Blues didn't let up, making it 10-3 in the third on Patrik Berglund's goal early in the period and Porter's second goal of the game with 2:10 left long after most of the fans walked left the building.
"It seemed like they had an extra guy out there," MacDonald said. "We haven't played like that all year."
Actually, it has been a lot of years.
The last time Detroit gave up eight goals in the first 40 minutes of the game was March 3, 1986, when it lost 12-3 to Edmonton. The Red Wings allowed 10 goals for the first time since Oct. 9, 1993, in a 10-3 setback against the Los Angeles Kings.
"You're usually trying to keep them from putting up double digits," Backes said.
- Howard, sidelined by a sore left shoulder, hopes to play Saturday at Nashville.
- Blues center T.J. Oshie served the second game of his two-game suspension for missing practice Monday, but general manager Doug Armstrong would only say the franchise would re-evaluate the situation Thursday.
- Detroit C Pavel Datsyuk missed his sixth consecutive game with a lower-body injury.