BOSTON -- What makes Team USA a team -- and not just a collection of All-Stars -- is having Jaccob Slavin on the roster.

That's not conjecture. That's what Team USA coach Mike Sullivan said when asked what the Carolina Hurricanes defenseman means to the men's national team at the 4 Nations Face-Off.

Practically everything about Team USA is a spectacle. The way they win is a spectacle. Their personalities are spectacles upon spectacles. Even hearing the song "Free Bird" after each goal is a spectacle; the reaction it draws from Team USA's fans comes with the expectation that a bald eagle is going to soar throughout the arena to the backdrop of fireworks.

And while Slavin is the antithesis of that spectacle, what he does for the team is one of the main reasons the spectacle exists in the first place. Goals and those who score those goals receive the bulk of the attention. Goal prevention is not always guaranteed acclaim.

But this is what defines Slavin. It's also what could help America sit atop the hockey world with another win over Canada in the 4 Nations Face-Off final (8 p.m. ET, ESPN/ESPN+/Disney+).

"He's so underrated and he's honestly one of my favorite players to watch," Team USA defenseman Jake Sanderson said. "He just flies under the radar and makes great plays. He's so solid defensively and such a great skater. It's the sort of attribute I want in my game someday."

LEADING INTO THE TOURNAMENT, a big talking point was what Team USA's defensive structure would look like. While Connor Hellebuyck was long believed to be the starting goalie, there was a thought that whoever would be in front of America's goalies was going to give opponents fits.

The U.S. created a defensive corps featuring Brock Faber, Adam Fox, Charlie McAvoy, Zach Werenski, Noah Hanifin and Sanderson. Those six skaters are part of a larger wave of puck-moving defensemen who've helped define the NHL's newest glamour position.

It's a group that initially included the reigning Norris Trophy winner, Quinn Hughes, who was ruled out because of an injury.

But that also comes with the caveat that the rise of those puck-moving defensemen has led to defensive-minded defensemen receiving less attention.

Or to view it another way: The NHL's affinity for two-way quarterbacks has come at the cost of those shutdown defensemen. And if his Team USA teammates are quarterbacks for what they do in the offensive zone, that in turn makes Slavin a shutdown cornerback.

"Jaccob's a guy that, in my mind, is one of the best defenders and one of the best defending defensemen in the league," Sullivan said. "His size, his mobility, his reach, his ability to read plays, he closes on people, how strong he is in the battle areas. I don't know if there's a defenseman in the league who defends the rush more aggressively or better than Jaccob does."

MANY THINGS HAVE CONTRIBUTED to why Team USA has looked like the most consistently complete team throughout the 4 Nations tournament. One of those is a restrictive defensive structure that, if all else fails, can rely on Hellebuyck, one of the greatest goaltenders America has ever produced, to contain the situation.

Actually getting to that point against Team USA has been rare for opponents. Finland scored only once, as did Canada. The U.S. won both of those games, which made Monday's 2-1 loss to Sweden irrelevant because it had already qualified for the title game.

The most surprising part of Sweden's two goals? Slavin was on the ice for both.

Before that, he had logged more than 45 combined 5-on-5 and short-handed minutes without a goal being scored. He leads Team USA's skaters with an average ice time of 21:31 per game, while anchoring a penalty kill that hasn't allowed a power-play goal against.

"He's super tough to play against. I'm a D and I don't go against him a lot," Sweden and Tampa Bay Lightning defenseman Victor Hedman said. "The way he is in the way, the way he breaks pucks up and is such a great skater."

Much of what Slavin does is in the details, but there are times when it becomes large enough for all to see. That was the case in the win over Canada, when Colorado Avalanche superstar center and reigning Hart Trophy winner Nathan MacKinnon was speeding in for a zone entry, as he has done so often in his NHL career.

Just when it appeared MacKinnon found an opening, Slavin was right there -- forcing one of the game's most dangerous players to rethink his approach.

"Yeah, he's incredible defensively and does a lot of little things that are hard to notice," said Hanifin, who was teammates with Slavin for three seasons in Carolina. "Just his stick. He breaks up so many plays that are hard to break up.

"He's a great skater; he's always gapping up and limiting an opponent's time and space. He's one of the best in the game at it."

TEAM USA AND Dallas Stars goaltender Jake Oettinger said that he always knew that Slavin was underrated, but actually playing with him at the 4 Nations gave him a greater appreciation for what he does.

"He takes away stuff before it ever happens," Oettinger said. "It never has time to develop, and he just reads the game so well and is so smart. I'm sure those goalies in Carolina love playing for him."

Slavin does have an offensive presence. He has had seven seasons of more than 30 points, and is flirting with what would be an eighth season, with 20 points through 56 games this NHL season. In total, he's had 292 points in 721 career games. For comparison, Hughes has scored 392 points in just 412 games.

But another detail that speaks to Slavin's effectiveness is how he's low-risk for penalties, despite consistently playing in high-risk situations (for copious minutes) on a nightly basis.

The 30-year-old Slavin is averaging more than 22 minutes per game for his career, yet he has accrued only 94 total penalty minutes in those 721 games. Another comparison: Team USA forward Brady Tkachuk finished second in the NHL with 134 penalty minutes last season.

Sullivan explained that Team USA wanted to build the sort of well-rounded team that could thrive in whatever situation was presented.

By adding Slavin to its roster, Team USA has done more than thrive in all situations at the 4 Nations Face-Off. And now, he has put them in position to win it all.

"He's been a big part of our group's ability to be stingy defensively," Sullivan said. "He's a huge part of our penalty kill. He helps us at our net front. Those are the types of skill sets or complementary skill sets we were looking for when we were putting this group together.

"He may not be the guy that ends up on the scoring sheet or on ['SportsCenter'], he's just the guy that helps you win."