The Montreal Canadiens and Pittsburgh Penguins took direct aim at New Jersey on a night the pacesetting Devils had no defense against either challenger.
With the Devils enjoying a night off between key games against New York's Rangers and Islanders, the Canadiens passed them Thursday for first place in the Eastern Conference while the Penguins caught them for a share of the lead in the Atlantic Division.
The Penguins (42-25-7) have played one more game than the Devils (42-24-7), and the clubs are separated by a mere regulation loss. New Jersey, which faces the Islanders at home on Friday night, trails Montreal by one point, but has two games in hand.
Montreal regained the top spot in the East on Thursday with a 4-2 win over the Bruins in Boston. It was the Canadiens' 10th straight win over their Original Six rivals, tying their best run in the long history of the franchises.
The Bruins have dropped all seven meetings with the Canadiens this season and Boston has just one more chance to beat them. The Bruins might need that road win Saturday to stay in a playoff position.
Alex Kovalev had two goals and an assist, and Carey Price made 34 saves for the Canadiens, who set their consecutive wins mark against Boston in the 1944-45 season.
"Some teams just play well against other teams, and that's just the way it goes," Price said.
Evgeni Malkin had a goal and an assist, and the Penguins tied New Jersey atop the Atlantic by beating the Tampa Bay Lightning 4-2.
In other NHL games, it was Ottawa 3, St. Louis 2; Carolina 2, Florida 1 in a shootout; Detroit 6, Nashville 3; Vancouver 4, Edmonton 1; Calgary 2, Colorado 1; and Los Angeles 6, Phoenix 5 in a shootout.
Jordan Staal and Petr Sykora scored 16 seconds apart during the first 51 seconds of the third for the Penguins, who have won four of five and beat Tampa Bay at home for the first time since Nov. 2, 2002.
The Penguins have eight games to play - two against each division rival. Despite being only a point out of first in the conference, they also only lead the sixth-place Rangers by four points.
"It's such a tight race, you know?" said Marc-Andre Fleury, who made 19 saves to improve to 5-1 since returning from an ankle injury. "Every point we can get is good for us."
Filip Kuba and Vincent Lecavalier each had a goal and an assist, and Jussi Jokinen had two assists for the Lightning, who allowed six third-period goals to Buffalo in a 7-4 loss Wednesday.
Lecavalier's goal was his 40th after he led the NHL with 52 last season. He is third in the league with 90 points, but the Lightning have the worst record in the East.
"When you don't make the playoffs, (the scoring race) is not as gratifying," Lecavalier said.
The seventh-place Bruins are only two points ahead of Buffalo, which is on the outside of the postseason race. Both teams have eight games remaining.
"The onus is on us to change this," Bruins defenseman Aaron Ward said of the struggles against Montreal. "It sounds bad to say, but I thought we were better against them tonight. Shame on us if we are not ready for them on Saturday."
Jason Spezza scored his 31st goal and Martin Gerber stopped 24 shots for the host Senators.
Antoine Vermette and Christoph Schubert also scored for Ottawa, fifth in the Eastern Conference with 89 points, two more than the Rangers.
The Senators remained three points behind Montreal.
Jamal Mayers and Jeff Woywitka scored 2:44 apart midway through the first period to give St. Louis a short-lived 2-1 lead.
At Sunrise, Fla., Sergei Samsonov and Eric Staal scored in the shootout for Carolina, which snapped Florida's team-record tying win streak at seven.
Trevor Letowski scored in the first period for Carolina, which won for the 10th time in 13 games. The Southeast Division-leading Hurricanes have 87 points, seven more than second-place Washington.
Stephen Weiss scored the only goal for the 11th-place Panthers, four points behind seventh-place Boston and three behind eighth-place Philadelphia.
At Nashville, Tenn., Johan Franzen scored in the third period for Detroit.
Niklas Kronwall, Chris Chelios, and Brian Rafalski each scored second-period goals for the Red Wings. Dominik Hasek earned his 385th victory, tying Mike Vernon, who won a Stanley Cup with Detroit, for 10th on the NHL career list.
Alexander Radulov scored twice for Nashville, and Martin Erat had the other goal for the Predators, who lost their franchise record-tying sixth consecutive home game.
At Calgary, Alberta, Daymond Langkow and Craig Conroy scored first-period, power-play goals.
After a disappointing 1-3 road trip, Calgary improved to 5-0-2 in its past seven at home.
Ben Guite scored for Colorado, which has lost three straight after winning eight of nine.
At Edmonton, Alberta, Matt Pettinger's late second-period goal helped Vancouver win its third in a row.
Daniel Sedin, Taylor Pyatt and Trevor Linden scored the other Vancouver goals. Tom Gilbert scored for Edmonton.
The Canucks have won six of eight and moved into a sixth-place tie in the Western Conference, one point back of Northwest-Division leading Minnesota.
At Glendale, Ariz., Patrick O'Sullivan scored in a shootout for Los Angeles.
The Coyotes forced overtime with their fourth power-play goal, by Keith Ballard with 24 seconds left in regulation. Phoenix, which had won six straight over the Kings this season, is six points out of a playoff spot with seven games left.
It was the Coyotes' 19th loss at home. Only Los Angeles has a worse home mark.