Forty minutes after the Colorado Avalanche ended practice Tuesday, the center continued to rip pucks at the net at the north end of PPG Paints Arena. Most of his teammates had already showered, dressed and left the building by the time MacKinnon went to the dressing room.
Asked where the inspiration to continue refining his game comes from, he nodded in the direction of the Pittsburgh Penguins dressing room down the hallway.
"You learn from Sid," MacKinnon said, referring to Penguins center Sidney Crosby. "He always does extra. He wants more work. He's the one guy who'll get mad if it's not enough work.
"It's amazing to watch him."
Video: PIT@MIN: Crosby nets nifty backhander on break
Crosby is MacKinnon's mentor and one of his best friends. They are both from Cole Harbour, Nova Scotia, and work out together every offseason. They've filmed numerous commercials for Tim Hortons together.
In the immediate future, however, there is nothing MacKinnon wants more than for the Avalanche to defeat the Penguins on "Wednesday Night Hockey" (7 p.m. ET; NBCSN) in a game featuring two of the hottest teams in the NHL.
Colorado (5-0-0), the only undefeated team in the League, is coming off an impressive 6-3 victory at the Washington Capitals on Monday. MacKinnon had a goal and an assist, and has had at least one point in each of Colorado's games this season (eight points; two goals, six assists).
The Penguins (4-2-0) have won three straight games and have scored 14 goals over their past two, a 7-4 win at the Minnesota Wild on Saturday and a 7-2 win at the Winnipeg Jets on Sunday.
Crosby was named the NHL Third Star for the week ending Oct. 13 after his seven points (three goals, four assists) helped Pittsburgh go 3-1-0. He has 10 points (three goals, seven assists) in six games this season and, like MacKinnon, has had at least one point in each of his team's games.
"I think he's playing some of the best hockey of his career," the 24-year-old MacKinnon said of Crosby, who has won the Stanley Cup three times and been voted the Hart Trophy winner twice as NHL MVP. "It's all about how complete he is as a player. It's not just about points. And he still gets 100 a year. But the way he plays at both ends of the ice, I wouldn't take any player above him.
"For us, it's our sixth game of the season, so I don't think [expectations] are too heightened yet. We have seventy-seven still to go and our focus is on the numerous parts of our game we need to work on. But it's going to be fun playing against the best player in the world, one of the best players to ever play, not just for me but for everybody. Some guys have never played against Sid, so it's really cool for our young players to do that."
Work ethic isn't the only thing MacKinnon had learned from the 32-year-old. He's also fed off Crosby's competitive nature and will to win, so much so that the two friends have gotten into emotional scraps during offseason skates.
"We don't do much chirping to each other in games, but there's lots in the summer," Crosby said with a grin. "We're talking hockey a lot, going back and forth. And yeah, there's the odd little scuffle too. We're pretty competitive, and that tends to happen. You spend enough time around each other, and that tends to happen."
Video: BOS@COL: MacKinnon cleans up in front for PPG
MacKinnon said any animosity ends once they step off the ice.
"We're always on different teams on 3-on-3, so it gets heated," he said. "But as soon as we're in the dressing room, it's fine. It's over. He's not the type of guy that would ever let an argument linger. We both drop it right away. It's just the competitive juices coming out in the summer. I think it's great."
One of MacKinnon's favorite verbal jabs at Crosby during the offseason involved the first game between the Avalanche and Penguins last season, which Colorado won 6-3 at home Nov. 28. Crosby had a natural hat trick that night, but the Penguins couldn't overcome MacKinnon's four points (one goal, three assists).
"He always gives me a hard time, telling me how ugly some of those goals were," Crosby said with a laugh of the 2018 Hart runner-up. "You always remember them being nicer than they actually were. But he ended up getting the win, and he got four points, so there's nothing I can say.
"The thing about Nate: He works hard to be at his best every year. I think given where he's at and what he's achieved already, I think the ceiling is pretty high. I think with him, he cares so much about winning too. If that means getting a few less points to get a few more wins, I'm sure he's OK with that.
"Either way, he's going to put up a lot of points for a really long time."
Each player chuckled Tuesday when it was suggested this game is being touted as the Cole Harbour Bowl. To that end, MacKinnon said he wouldn't be surprised if their fathers, Troy Crosby and Graham MacKinnon, get together back home to watch their sons do battle.
"They're pals," MacKinnon said with a big smile. "They might very well have a rum and Coke and watch us play."