The top two teams entering the Stanley Cup Playoffs have been eliminated in the first round for the first time since the NHL expansion of 1967-68.
The Calgary Flames, the top team in the Western Conference in the regular season, were eliminated from the playoffs with a 5-1 loss to the Colorado Avalanche in Game 5 of a best-of-7 series Friday.
The Tampa Bay Lightning, who led the Eastern Conference, were swept by the Columbus Blue Jackets in a best-of-7 series that ended Tuesday.
Video: Lightning, Flames eliminated from playoffs early
Since 1967-68, when six teams were added to make the NHL a 12-team league, there have been a number of playoff formats: division-based, conference-based, and for two seasons (1979-80, 1980-81) the top 16 teams were seeded by regular-season points.
In none of those instances had the top two teams in each division or conference, or the teams with the two best records, been eliminated in the first round of the playoffs.
Video: COL@CGY, Gm5: Avs, Flames shake hands after Game 5
Tampa Bay (62-16-4) tied the NHL record for wins in a season, set by the 1995-96 Detroit Red Wings, and finished 21 points ahead of the Boston Bruins in the Eastern Conference.
"The Presidents' Trophy won't help any team to win in the playoffs," Lightning goalie Andrei Vasilevskiy said of having the best regular-season record.
Calgary (50-25-7) led the Western Conference by six points over the San Jose Sharks.
The Lightning lost four straight games to the Blue Jackets and were outscored 15-5 in the final three, including 7-3 in Game 4.
"We as a group, I wouldn't say we're in shock, but we're just disappointed that we couldn't execute," Tampa Bay captain Steven Stamkos said. "We knew it wasn't going to be easy. Just because you have the regular season that you do, it's not like we're just handed a series or a trip to the [Stanley Cup] Final. You have to earn everything. We got beat by a team that was better than us during that [seven-day] stretch. There's really not much we can say."
Video: TBL@CBJ, Gm4: Jackets, Lightning shake hands
The Flames lost four straight games after winning Game 1. The Avalanche won Game 2 and Game 4 in overtime.
"It's a hard season to get into the playoffs. It's so competitive. Once you're in there anything can happen," Calgary goalie Mike Smith said. "... I didn't think we played our best consistently throughout this series and you have to do your best if you want to move on. You can't move on just being average."
The Bruins, who like the Flames had 107 points this season, are the highest-finishing team remaining in the playoffs. But Boston is one game from elimination after losing to the Toronto Maple Leafs 2-1 in Game 5 on Friday. Game 6 of that series is Sunday at Toronto.