LOS ANGELES — They gathered together for the first time two weeks ago, unsure what to expect in the World Baseball Classic, with a sense of insecurity that they even made the right choice to play in this international tournament.

Now, here they are after defeating Japan, 2-1, on Tuesday night, going where no USA team before them has ever gone before.

For the first time since this tournament started 11 years ago, Team USA is playing for the championship, facing Puerto Rico at 9 p.m. ET on Wednesday night at Dodger Stadium.

It might seem like a glorified exhibition game to most of America, but for the USA team, it means more than anyone could have possibly envisioned when they began this journey.

“Besides making my first All-Star Game, which was in Minnesota where I grew up,’’ said USA reliever Pat Neshek, who got the biggest out of the game Tuesday, “this is the best thing I’ve done. Nothing can beat this.

“You know, I’ve never been a prospect. Nobody really ever considered me for a Team USA. You get here, and you see these other teams, and how much fun they have. It pumps you up.

“I’ve never been in the World Series, but I’ve been in a lot of playoff games, and this is better.

“Really, it’s the best.’’

Really, no matter the outcome of the championship game, Team USA has lifted this tournament into what Major League Baseball and the players association envisioned when it was first created.

There have shattered attendance records, drawing in excess of one million fans, with 33,462 coming out Wednesday to Dodger Stadium on a cool, rainy evening.

“Who would have thought we’d be playing in this type of game in Los Angeles?’’ said Pittsburgh Pirates All-Star outfielder Andrew McCutchen, who drove in the first run of the game. “I don’t think I’ve ever seen this type of weather in the years that I’ve come here. That’s what makes this game amazing.’’

Then again, the majority of these players on Team USA never imagined they’d be playing in this type of atmosphere in March.

This is usually the dog days of spring training, when players are more interested in packing their bags, and loading up their cars, than playing the final week of games in Arizona and Florida.

Yet, these games are like playing postseason games before the real season even starts, with fans banging on noisemakers, beating on drums, sounding horns, slapping tambourines, and screaming as if it’s a combination of the World Cup and Super Bowl.

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“I remember in ’06, my rookie year, this thing was kind of laughable,’’ Neshek said. “It was like, ‘What is this garbage?’ Then you had the one in ’09, it was ok. And then the last one in ’13, you think, this is kind of serious.

“Now, after what we’ve done, the way everybody is buzzing about it on Twitter, and all of the attention it’s getting, you’re going to see everybody in the league want to pole in the next one. It’s a big deal. You won’t see a guy say, “No.’’’

It’s why San Francisco Giants closer Mark Melancon didn’t feel comfortable leaving his new teammates when he arrived to spring training, but told teammate Buster Posey that if it were possible, he’d love to join them in the second round. Joe Torre, the architect of the team, called last week, and there was Melancon making his WBC debut in the eighth inning.

“I’ve been watching this tournament pretty closely on TV,’’ Melancon said, “and it energized me. I felt like this was the first WBC tournament that has really taken off. Everybody is really into it, and excited.

“It’s different because your body clock kind of gets jolted into this, but it’s a good thing bridging the gap from spring training into the season.’’

Yep, tell Neshek about it. He came into the game in the eighth inning with two outs, runners on first and second, and left-handed cleanup hitter Yoshitomo Tsutsugoh coming to the plate. Neshek thought it was a right-handed hitter, so he threw sliders in the bullpen, never imagining he was facing a lefty who was their best slugger.

Neshek, who didn’t even know it was a left-handed batter until catcher Buster Posey came to the mound, started him off with a changeup, and on the fourth pitch, threw another. Tsutsugoh took a huge swing, and just missed it, with the ball falling softly into the glove of McCutchen in right field.

Neshek threw his hands into the air, jogged off the field, looked at Posey on the bench, and rolled his eyes in relief.

“”This thing is so intense,’’ Neshek said. “I really haven’t had much room for failure in this thing. If they get a hit there, I’m the worst player ever.

“It reminded me of ‘14 with the Cardinals when Matt Adams hit that homer off [Clayton] Kershaw. I said, “Oh, my God.’ I don’t want to blow it.’ That’s the way I felt.’’

Team USA, which went ahead 2-1 on Adam Jones’ slow infield roller that scored Brandon Crawford from third base in the eighth inning, hung on for the victory with Luke Gregerson pitching a 1-2-3 ninth inning.

Now, they find themes in playing the most important international baseball game for the U.S. since Hall of Fame manager Tommy Lasorda led the Olympians to the 1990 gold medal.

For Team USA, it’s a chance to make history, showing the world that they might not have had their greatest players in the tournament, but still are the best.

For Team Puerto Rico, well, it means everything, showing an unbridled passion and energy you won’t even find in a World Series. Veterans such as Carlos Beltran and Yadier Molina insist that winning the WBC would be the highlight of their magnificent careers.

“I think certainly playing for their country,’’ USA reliever Andrew Miller says, “brings out the best in them. I think we have to try to match that. It’s not like we’re not proud to play for USA, but certainly there’s an energy these teams have brought that we’ve had to fight against.

“It’s a challenge.’’

And you can imagine the emotions USA starter Marcus Stroman will feel when he takes the mound. He could have easily been starting for Puerto Rico instead of Seth Lugo, since his mother is Puerto Rican. He even considered playing for Puerto Rico until deciding that he belonged on the USA team, where he grew up on Long Island, N.Y., and graduated from Duke University.

“It was a tough choice,’’ Stroman said. “My mom’s born and raised in Puerto Rico. But at the end of the day, getting that call from Joe Torre, I couldn’t say, “No.’ I played for Team USA for the collegiate national team in 2011, so that also had something to do with it.

“I feel like in the end I made the right choice.’’

Now, we have the title game that everyone wanted to see, and while Puerto Rico is undefeated and has stolen the show with their exuberance and demonstrative celebrations, USA vows to let loose if they prevail.

“I know I will,’’ Neshek said, laughing. “We’ve got a [decorative] big giant eagle in our clubhouse, and I’m bringing that sucker onto the field.

“I think a lot of guys don’t really want to go nuts until we’re the best, but if we win that thing, look out.’’

Then, once and for all, everyone will be able to see the WBC at its best.

Follow Bob Nightengale on Twitter @Bnightengale and on Facebook.

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