SEATTLE — The Seattle Sounders achieved their biggest moment in the city’s soccer history on Sunday by winning MLS Cup, 3-1 over Toronto FC, in front of a record 69,274 fans at CenturyLink Field. But to those in charge, the achievement does not mean scaling the top of the mountain. Instead, it's merely a springboard to even greater heights, both on and off the field.

Despite winning MLS Cup in 2016, getting to the final a year later and being the envy of many MLS clubs with 40,000 average attendances, the Sounders hadn't given their city a chance to watch its team take the field in the league's biggest game on home soil.

Sunday changed everything.

“Doing in front of the home crowd, doing it front of 69,000 fans, one of the biggest sporting events in Seattle history, now we’re not just relevant in MLS, we’re relevant in the city,” said Sounders general manager Garth Lagerwey moments after his team’s triumph. “And I think that’s a big deal.”

Sunday was a very big deal. For days, Sounders green has lit up Seattle with mentions of MLS Cup plastered throughout the city. It’s been impossible, even for the soccer novice, to ignore. Despite the early kickoff, thousands of fans decked in Sounders colors lined the city's streets for the march to the match. Even more packed into CenturyLink Field, more than had ever attended a Seattle Seahawks NFL game at the same venue.

One of those soaking in the atmosphere before the game was someone largely responsible for making it all possible, majority owner Adrian Hanauer.

“I came down early to Pioneer Square and to see people everywhere at 8 in the morning on a Sunday is kind of crazy,” he said. “I realized it was going to be big. Our great new partner Macklemore performing before he normally has his cup of coffee was pretty cool, and the whole day overall was pretty special.”

The game and the team had truly taken over the city. Already, the aim is to turn many of those who showed up and made their voices heard on Sunday into regulars at CenturyLink in 2020 and beyond.

"If we can just get 50,000 of them to say, 'I want to be a season ticket holder because that was a pretty good show tonight,' then we’re going to take that next notch up that next step," said Lagerwey.

That next step also involves growth on the field.

After a second MLS Cup title, and third final, in four years, the word “dynasty” has been put forward by many to describe what the Sounders have accomplished. But Lagerwey, who is realistic about how his team struggled at times during the regular season, is not one of them.

“I think you’ve got to win at least three to do that,” he said, even in the moment of his greatest triumph, as beer poured around him in the locker room.

As well as a third MLS Cup title, Lagerwey made it clear that the club aims to become the first MLS team to win the Concacaf Champions League.

“That’s the next mountain to climb, baby,” said the 46-year-old, whose experience with CCL dates back to his time as general manager with Real Salt Lake.

“It’s a dream we started in Salt Lake in 2010 when we became the first team to beat a Mexican team. It’s been a goal in Seattle. It will be a fun challenge.”

That challenge, Lagerwey acknowledged, means making some adjustments to the construction of their 2020 squad, and several questions hang over one of the league's oldest rosters. The club reportedly holds an option on inspirational defender Roman Torres, while left-back Brad Smith's loan from Premier League club Bournemouth will expire at the end of the year. Captain Nicolas Lodeiro, meanwhile, has previously made no secret of his desire to return to Boca Juniors.

“With the Champions League coming up, it’s only a nine-week turn in the offseason," Lagerway said. "I think you look at your vets and you say can we get one more run out of them. But I haven’t talked to them yet and there are going to be some guys who are going to have some fun, be overjoyed for a little bit, as they should be. But everyone’s gotta think about their own career and where they're gonna be and we've got some guys on loan, and we’ve got some guys out of contract and there'll be a lot of stuff that happens the next couple of days."

Coping with the demands of competing on multiple fronts has been a downfall for MLS clubs before. But the Sounders are determined that their run of making it to 11 straight postseasons won't be disrupted. To do that, Lagerwey said, they'll need to lean on their academy to deliver young starlets to beef up their roster.

For the Sounders, even in the midst of their greatest moment, the work never stops.

"Parade on Tuesday and we'll talk to everybody on Wednesday and see who wants to come back and who doesn’t," said Lagerwey.