No one understands better how extraordinary this Union season has been than Jim Curtin. And no one knows better how much it took just to have the chance at it.

Finishing first in the Eastern Conference didn’t just require matching Western Conference winner Los Angeles FC for points, only to miss the Supporters’ Shield on the tiebreaker of total wins instead of winning it on soccer’s traditional goal difference.

» READ MORE: How Jim Curtin developed a culture of success and style for the Union

It required holding off Montréal’s late charge on the final day of the season. It required a goal-line clearance to break the record for the stingiest defense in a 34-game MLS season. It required smashing the team’s single-season records for wins and goals, and becoming just the third team in MLS history with a net goal difference above plus-40.

It required going unbeaten at home all year, 12 wins and seven ties; setting a team record for away wins, seven; and having three players hit double digits in scoring, including Dániel Gazdag’s team-record 22 goals.

“To have it click like it did in the summer, I can’t say I was prepared for [it], our fan base was prepared … I think even our players and locker room,” Curtin told The Inquirer. “We knew we had a good team, but did we know we had a record-breaking team? I would say no.”

It’s only been nine months since the Union got rid of their top scorer from last year. It’s been seven months since they traded perhaps the most talented two-way midfielder in team history. Just three months ago, the team dumped its best super sub for the last 3½ years.

How did the Union emerge better than they’ve ever been? The Oreland-born Eagles fan in Curtin knows.

» READ MORE: The Union celebrate breaking Major League Soccer’s decade-old record for the stingiest defense

Just as the infamous Brian Dawkins trade proved the right thing to do, Union sporting director Ernst Tanner got it right moving on from Kacper Przybylko, Jamiro Monteiro, and Sergio Santos.

Przybylko wanted a big-money contract extension after scoring 17 goals last year, but he scored in only 15 of the 43 games he played. Chicago paid the Union $1.15 million, then paid Przybylko, and he scored just five goals this year.

“We knew we had a good team, but did we know we had a record-breaking team? I would say no.”

Monteiro’s departure was the hardest. Had relations not soured between his camp and the Union’s front office, perhaps he’d have stayed in a city he really liked. But he also would have blocked Jack McGlynn’s playing time.

San Jose offered what Monteiro wanted, the Union let him go, and McGlynn and Leon Flach flourished. Monteiro has been great this year, but for the Western Conference’s last-place team.

Santos was wonderfully entertaining but frustratingly injury-prone. His contract was up after this year, and the Union weren’t inclined to raise his $918,000 salary. Cincinnati called, the Union said yes, and in 10 games there Santos has two assists and no goals.

Of course, the second of those assists came in Saturday’s playoff win at the New York Red Bulls. Santos will return to Subaru Park for the first time since the trade for Thursday’s Eastern Conference semifinal (8 p.m., FS1 and Fox Deportes). But on the whole, the Union got that deal right.

“As a GM, it’s their job to recognize the right moment to maximize your assets, and that’s something that I’ve really learned from Ernst,” Curtin said. “His timing with that is 100%, perfect, which is hard to do.”

» READ MORE: Sergio Santos helps FC Cincinnati set up a reunion with the Union in the playoffs

When it comes to buying players, Curtin still believes the Union’s margin for error is small, even as the team is finally spending serious money on talent.

“It’s the thing that could set back the franchise a couple of years, too, if you get these big decisions wrong,” he said, “and Ernst has been incredible at getting those right.”

Here, too, the Union won three bets: Dániel Gazdag (22 goals and 6 assists this year), Mikael Uhre (13 and 6), and Julián Carranza (14 and 6).

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Those bets weren’t as big as other teams’. Atlanta United has spent over $50 million on transfer fees in the last three years but missed the playoffs in two and crashed in the first round of the other.

The gusts on those whiffs blew halfway to Canada, but Curtin barely felt them.

In the early years of Curtin’s tenure, he could walk from his Queen Village home to his favorite Mexican restaurant in the Italian Market without being recognized. He could go watch his kids play soccer at Capitolo Playground on a Saturday morning before coaching a game in Chester that night, and be just another parent on the sideline.

Not anymore.

“It’s increased exponentially,” Curtin said.

Earlier this year, his son, 10-year-old Miles, told him, “You actually get recognized way more in the suburbs than you do in the city.” That may seem true to a kid’s eyes, but the 43-year-old father knows better. Those trips to the suburbs are more rare, and they’re usually to watch 14-year-old daughter Ryan play in youth soccer tournaments. That audience is more likely to watch Curtin on TV every weekend.

“I think the people in the city maybe are more — respectful is the wrong word, but they’ll more just walk by and they’ll say hello,” Curtin said. “Whereas in the suburbs, it’s like, ‘Can you sign this? Can you do this?’ ”

» READ MORE: Why Andre Blake is the most important player in Union history

They all have something in common: They know a winner when they see one.

“I think part of it is the success of the team, I think part of it is the popularity and growth of the team,” Curtin said. “And the longevity that I’ve been here, all those things factor into it — and the fact that I’m 6-foot-4 and have long, curly hair.”

Curtin and his wife moved to Queen Village after his playing days ended. They liked it so much that they committed to stay and raise their kids there, and they’ve kept to it.

But it all could have come to an end last winter — with a move far beyond the suburbs

When big-spending FC Cincinnati hired Chris Albright from the Union to be their general manager last October, he wanted to bring his former Council Rock Dynamo youth soccer teammate over with him. A few days before the Eastern Conference final, Albright made a brazen call to the Union to try to poach Curtin.

Tanner blocked it, as he was allowed to do by MLS rules. Albright then went for Union assistant Pat Noonan, which Tanner couldn’t stop, and the Union blessed that. Noonan had been a candidate for many vacancies by then anyway, so Tanner knew Noonan would leave eventually.

Curtin didn’t shy away from the matter then, and he still doesn’t now.

“There was nothing really secretive or behind the scenes about it,” he said. “I want to coach in this city until we win an MLS Cup. So I’m content with it and happy.”

But he also knows his contract is up after next year, and that moment gave him leverage. So did a move by another longtime friend, Jesse Marsch, to become Leeds United’s manager in England’s Premier League. If things ever go sour for Curtin here, he’ll likely have a place to go for as long as Marsch is there.

Is it a coincidence that in the same winter when Albright settled in Cincinnati and Marsch joined Leeds, the Union made two big striker signings in Mikael Uhre and Julián Carranza? The team had never made an offseason splash that big, either in dollars or status.

“I didn’t demand anything,” Curtin said. “I’ve never gone to [principal owner] Jay Sugarman and asked for a new contract, I’ve never gone to Jay Sugarman and asked for new players. I’ve never asked for him to spend more. … Even with Ernst, I’ve never knocked on Ernst’s door and demanded a new whatever position.”

That prompted a skeptical glance from across the table. Was this the same Curtin who has plenty often lamented out loud when opposing teams had more talent?

“I think that I’ve taken the approach to take every situation and maximize it,” Curtin said. “Maximize the environment for the players, try and get the most out of each individual guy within the guidelines of our structure.”

In other words, perhaps he didn’t literally go to Sugarman and ask for new players. But now he shouldn’t have to. The current stars have proven why Sugarman needed to open his checkbook and leave it open.

Uhre paid off his team-record $2.8 million transfer fee with his goals, assists and leadership. Carranza was so good that the Union paid Inter Miami for his loan purchase option before they had to, and took on a likely raise to his already-sizable salary.

Behind them, Gazdag’s historic campaign blew up the plan to give Paxten Aaronson major minutes this year.

Now the rewards have come: a first-round playoff bye, a return to the Concacaf Champions League, and the best chance the Union have ever had to win their first MLS championship.

On Thursday at Subaru Park, that quest will officially begin.