VANCOUVER — Just before 10 a.m. West Coast time on Tuesday morning, a charter bus packed to capacity will pull out of Seattle. It won't be a quiet bus; chants will be yelled and perhaps some booze will be guzzled by fans decked out in red, white and blue.

A couple hours later, the bus will cross the Canadian border and arrive in downtown Vancouver. More than 50 members of the Seattle chapter of the American Outlaws — U.S. soccer's most prominent supporters' group — will disembark, swaggering into bars and exploring the town. By late afternoon, they'll help pack BC Place Stadium, where the U.S. takes on Nigeria in its Women's World Cup Group D finale at 5 p.m. local time.

Sounds great. The only problem? The American Outlaws should have chartered more busses.

Sean Kramer, a spokesperson for the American Outlaws' Seattle chapter, says his group underestimated the demand for seats on the trip up to Vancouver, learning too late that they could have filled at least one more bus.

"We've seen an overwhelming response of people who wanted to buy tickets," Kramer told Mashable on Sunday. "And we're just bringing a small chunk of the Cascadian contingent up to that match."

The packed bus from Seattle personifies a prominent storyline so far from the 2015 Women's World Cup in Canada: Robust support for a talented and hyped American team seeking to win its first trophy since 1999, when the U.S. hosted the tournament and Brandi Chastain famously disrobed in celebration to land herself on the cover of Sports Illustrated.

The team in Canada this summer is drawing support from near and far, creating a distinct home-field advantage. And its players are taking notice.

"You look up from the field and you just see red, white and blue," U.S. defender Ali Krieger said on Monday in Vancouver. "That's been really inspiring for all of us and gives us an extra energy that I don't think we had maybe before in different tournaments."

Big goals, big border lines

U.S. players have made no bones about it leading up to this tournament — their goal is to win the whole she-bang, and they have no doubt they possess the talent to do just that. But after some sluggish warmup performances this spring and two up-and-down efforts to open the World Cup, they still need to find their top gear.

The Americans opened their gauntlet through the tournament's so-called "Group of Death" with a 3-1 win over Australia last Monday, then slogged through a 0-0 draw with Sweden on Friday. The stakes against Nigeria on Tuesday are simple: Win the match and win the group. A tie — or an upset loss — makes matters more complicated. Chief among the Americans' concerns is slowing 20-year-old sensation Asisat Oshoala, a speedy forward with a nose for the goal.

U.S. coach Jill Ellis and defender Ali Krieger at a Monday press conference before taking on Nigeria on Tuesday. Image: Sam Laird/Mashable

"There's a lot at stake for both teams, so I'm expecting a very competitive match against a very quality opponent — it's going to be a challenging game for us," U.S. coach Jill Ellis said Monday in Vancouver.

What there's no doubt about is that the U.S. will have plenty of support.

The night before the U.S. opened its World Cup last Monday against Australia in Winnipeg, Manitoba, one border crossing into the province saw wait times up to three-and-a-half hours, a Canada Border Services Agency spokesperson told Mashable. The agency expected a similar deluge into British Columbia ahead of Tuesday's date with Nigeria.

As of Sunday night, there were fewer than 100 tickets left for Tuesday's match at BC Place; an organizing committee official said a crowd of more than 51,000 is ultimately expected. The previous two U.S. matches sold out as well. That contrasts with oftentimes piddling crowds for matches not involving the U.S. or host Canada — just 21,861 total fans showed up for four opening-round games in two cities last week, for example.

Supporters aren't all of the hardcore variety bussing down from Seattle, however. On Monday, a day out from the USA's first match in Vancouver, the FIFA Fan Zone erected in a parking lot two blocks from BC Place was already several times more packed than it had been late last week before matches involving Japan, Cameroon, Switzerland and Ecuador.

USA shirts were prominent on kids and parents milling about. One fan named David Rosowsky sat at a wooden picnic table decked out in a blue U.S. jersey after flying in from Las Vegas with his wife and their two sons a few days earlier. He said Tuesday against Nigeria would be the first time any of them had attended a U.S. women's game.

USA forward Sydney Leroux in action against Sweden last Friday. Image: Terrence Lee/Icon Sportswire/Associated Press

Overall, more than a million tickets have been sold for the entire tournament. (This is, however, a slightly misleading stat because some group-play matches are set as double-headers and fans must buy one ticket for both games, which organizers count as two tickets sold.) Ninety-five percent of those purchases have been by Americans and Canadians, according to a tournament official, who said they did not have numbers for individual countries.

But backing for the U.S. isn't only coming from fans who cross the border. It's also swelling stateside and reveals a rising tide of support for U.S. women's soccer.

Can the U.S. deliver on fans' high hopes?

As a banner in Winnipeg last week showed, only one result will make this tournament a success for the U.S. Image: Terrence Lee/Icon Sportswire/Associated Press

Four years ago Kramer's American Outlaws chapter held an official watch party at its home bar, The Atlantic Crossing in north Seattle, for the 2011 Women's Cup Final, when the U.S. lost to Japan in a classic thriller. A decent crowd showed up, but nothing too crazy. By contrast, the pub was packed to standing-room-only on Friday for the USA's group-play showdown with Sweden.

That same match set viewership records for Fox. An average of 4.5 million people tuned in to make it the highest-viewed soccer broadcast of Fox of all time, eclipsing the 2.6 million people who watched the 2011 UEFA Champions League final between iconic professional clubs Manchester United and FC Barcelona. Only three women's soccer matches have been more-watched in U.S. women's history — the 2011 final, and the 1999 semifinal and final.

But rest assured, if this U.S. team can go far in the knockout stage, the crowd rooting it on will only increase — at the Atlantic Crossing in Seattle, at the venues in Canada and in front of televisions back home.

"I think there's a feeling that this is a team that deserves all of our support because of the quality of the players, the personalities and the mission they are on," Kramer told Mashable.

Now it's up to Ellis, Krieger and company to pay back that support, starting with a strong finish to group play against Nigeria on Tuesday.