Los Angeles (16-7-4) has gone 1-1-3 in its last five overall since a four-game winning streak, and a sputtering power play is partially to blame. The Kings have gone 0 for 18 with the man advantage in the past five.
They failed to convert three chances in Saturday's 2-1 loss to Calgary, their fourth regulation home defeat of the season that matches last season's total. Los Angeles has managed two goals during the three-game home skid.
"We have to find that energy again," coach Darryl Sutter said. "We have played all of these overtime games in a row which adds a lot. I think we were lacking (emotion) tonight."
Justin Williams scored his team-leading 10th goal. He had 11 in 48 games a season ago.
Ben Scrivens made 18 saves in his first regulation loss since replacing the injured Jonathan Quick on Nov. 12. He has a .944 save percentage and 1.52 goals-against average.
"We will take what we can from this game, but it's a brand new 60 minutes and now St. Louis is here so we got to start getting focused for it," Scrivens said. "We will take what we can but we got to park it pretty quickly."
Los Angeles' eight-game home run against St. Louis includes playoffs, and the Kings have taken 14 of the past 17 overall matchups and four straight. The most recent meeting was a 2-1 victory May 10 that closed out a first-round postseason series after the Blues had won the first two games.
St. Louis (18-4-3) is trying to avoid losing back-to-back games in regulation for the first time this season after a 6-3 defeat at San Jose on Friday, snapping a five-game winning streak.
"We gained some back in the second and third (periods) but it was a matter of too little, too late," center David Backes said. "If you give any good team a four-goal lead you're asking for a loss."
Despite the Blues' struggles against the Kings, Halak is 6-4-0 with a 2.23 GAA and a pair of shutouts against them. He missed the playoffs last season with a lower-body injury.
Backes scored a third-period power-play goal Friday. He has four goals in his last five games, though he's gone without a point in his last seven regular-season contests against the Kings.
Los Angeles has allowed one goal in its last 21 short-handed situations.