The Dallas Stars ended a stretch against their top Western Conference competition with a clunker this week.
The Tampa Bay Lightning suffered a similar disappointment at the hands of the NHL's worst team.
While the Stars seek a rebound win to reignite their bid for the West's top spot, the Lightning hope to keep pace in the East's Atlantic Division when they meet in Dallas on Thursday night.
Dallas (41-21-9) opened a key five-game homestand with Friday's 5-2 victory over Chicago and Saturday's 5-4 overtime loss to St. Louis, the two other teams battling for the Central title.
Then the Stars' bid for the West's best record took a hit with Tuesday's 5-2 loss to Pacific-leading Los Angeles. Dallas' five-game point streak ended as it fell to 22-11-2 at American Airlines Center, tightening the four-team race at the top of the conference.
The Stars' goaltending concerns grew louder as they allowed at least five goals for the sixth time since Feb. 18. They are the league's only team with a 4.00 goals-against average while playing 13 games in that span.
Antti Niemi made 31 saves but allowed all five goals to the Blues, and he relieved an ineffective Kari Lehtonen against the Kings. Lehtonen surrendered four goals on 11 shots and was pulled just 1:07 into the second period before Niemi stopped 10 of the final 11 shots.
''This was a big letdown for us,'' coach Lindy Ruff said. ''I thought we came out flat. We knew that it was going to be a rough, tough game. They came out good, we came out casual.''
Lehtonen had just made 21 saves in the win over Chicago but remains neck and neck with Niemi at the bottom of the league in save percentage - owning a .903 mark, just better than Niemi's .901.
Both are on pace to be the worst marks in a Dallas uniform since Marty Turco's .898 in 2008-09 - though Lehtonen did finish at .903 last season.
Usually Dallas' offensive explosiveness is good enough to offset its defensive issues, but leading scorers Jamie Benn and Tyler Seguin were held without a point for just the 16th time. The Stars are 3-8-5 in those contests.
Each scored and assisted in Dallas' 5-3 win over Tampa Bay on Oct. 15. Five different Stars players tallied a goal for just their second win in the last seven games of this series.
The Lightning (40-25-5) have won five of six in Dallas since 2002-03, and they have won seven of their last nine road games.
However, Tampa Bay is coming off Tuesday's bitter 4-1 loss at Toronto. The Lightning have scored just eight goals in a 1-3-1 span, half coming from Sunday's 4-0 win at Columbus to open a four-game trip.
The Maple Leafs have the fewest points in the NHL but managed to snatch two away from Tampa Bay, which is in a tight race with Florida and Boston in the Atlantic.
''That was a really disappointing game,'' coach Jon Cooper said. ''One team came out to win a hockey game and the other team came out thinking they were going to win the hockey game. That was it. The right team won.''
Ben Bishop took the night off but has been solid in net with a 7-1-1 record since Feb. 20 and .957 save percentage in seven games since Feb. 26. He made 37 saves against the Blue Jackets for his fourth shutout.
However, he allowed all five goals on 22 shots in the October loss to the Stars and has an .868 save percentage in three career starts against them.