The Washington Capitals took out the NHL Presidents' Trophy for the second time in franchise history after a 4-1 win over the Columbus Blue Jackets.
Justin Williams scored to give the Capitals the lead 16 minutes, 30 seconds into the first period before Cam Atkinson tied things up just under two minutes later.
After a scoreless second period, the Capitals blew Columbus away in the third, with goals from Tom Wilson, T.J. Oshie and Nicklas Backstrom.
The win ensured the Capitals finished with the best record in the NHL with seven games left, which is the earliest a team has clinched top spot in the NHL since 2002.
However, Capitals coach Barry Trotz is wary his side need to concentrate on the post-season, saying: "There's not going to be a champagne party or anything like that.
"I think there's a sense of fulfilment that we said we were going to do some things and we've accomplished them so far, and we still have some things we've got to accomplish."
The San Jose Sharks sealed their play-off spot courtesy of a 5-2 win over the Los Angeles Kings.
The scores were locked at 2-2 heading into the final period but the Sharks proved too strong for the Kings, with Joe Thornton, Melker Karlsson making it 4-2 before Justin Braun scored a second, hitting into an empty net in the dying stages.
Claude Giroux scored an overtime winner for Philadelphia to help the Flyers maintain a wild-card lead over the Detriot Red Wings.
After leading 2-0 over the Winnipeg Jets, the Flyers conceded twice before captain Giroux scored with 14 seconds left in OT to secure a 3-2 win.
The Red Wings, meanwhile, made sure they kept up with the Flyers courtesy of a 3-2 victory over the Buffalo Sabres.
The Colorado Avalanche denied the Nashville Predators a chance to clinch a play-off spot, coming out 4-3 winners despite a late fightback from their opponents.
In other results, the Tampa Bay Lightning defeated the Toronto Maple Leafs 3-0, the Anaheim Ducks edged the Edmonton Oilers 2-1, and the Calgary Flames triumphed against the Arizona Coyotes 5-2.