All game, really, with Colorado going on 10 power plays to keep the Rangers on the defensive throughout.
Colorado finished with its most power-play opportunities since Oct. 16, 2008, when the team had 11 against Philadelphia.
''The way we've been struggling lately it feels so good to get a win,'' defenseman Tyson Barrie said.
Gabriel Landeskog added a goal off his right skate, Alexander Kerfoot tipped in a shot, Rantanen deflected in yet another and Ryan Graves closed out the scoring with his first career NHL goal as a struggling Avalanche squad won for the first time since Dec. 19.
Colorado finished 3 of 10 on the power play, with two of the goals scored following a 5-minute boarding call on former Avalanche player Cody McLeod just 2 1/2 minutes in.
''It's been losing hockey. It's been negative - negative video, a negative vibe around the rink,'' MacKinnon said. ''It's nice to finally end it.''
To Rangers coach David Quinn, this loss boiled down to one thing - all those penalties. The Avalanche had 15:23 of power-play time.
''You have zero chance to win a hockey game in that way,'' Quinn said. ''It wasn't our night from the get-go. We created a lot of our own problems with the penalties.''
Ryan Strome scored the Rangers' lone goal midway through third period on a night they were outshot by a 47-25 margin. Alexandar Georgiev attempted to keep things close while giving Henrik Lundqvist a night off. Lundqvist was pulled Wednesday after allowing six goals in a loss to Pittsburgh.
Barrie had three assists to give him 278 career points, the most by a defenseman in franchise history. Barrie broke the mark held by John-Michael Liles.
''Finally nice to get it out of the way and put it behind me,'' Barrie said. '' It's something I can look back on and take pride in it. Johnny's a great guy and a great player, so it's nice to pass him and take him out to dinner.''
After the morning skate, the Avalanche reiterated over and over the importance of a fast start to break out of their 0-4-2 skid.
This helped their cause: Going on the power play early when McLeod slammed the face of defenseman Samuel Girard into the glass on a big hit. MacKinnon scored on a high wrist shot over Georgiev's glove at 4:40, with Rantanen adding another 2:13 later when his pass went in off the stick of New York defenseman Neal Pionk.
''It's hard to play games when you sit that long in the box,'' Rangers forward Mats Zuccarello said. ''At the end of the day, they were the better team than us.''
Colorado was getting all the bounces, with Landeskog knocking in a goal with his right skate midway through the second period. The Avalanche led 5-0 in the third before Strome ended Grubauer's shutout bid on a breakaway.
Graves scored his first career goal following a rebound in the third. He was selected by New York in the fourth round of the 2013 draft, before being dealt to Colorado last February.
''Regardless of who we were playing, it's pretty sweet,'' Graves said of his goal.
NOTES: Rangers C Kevin Hayes missed the game with an upper body injury. ... Avalanche G Semyon Varlamov remains day-to-day with a lower body injury. ... The Avs are stumping for Landeskog to make the All-Star team through the ''Last Men In'' vote from the fans. There were buttons and signs that read, ''Vote Gabe in.'' ... MacKinnon and Landeskog each have 25 goals this season.
Rangers: Stop No. 2 on a three-game trip will be Sunday in Arizona.
Avalanche: Open a five-game trip Tuesday in Winnipeg.
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