Major League Soccer will celebrate the completion of its 20th season here on Sunday with the MLS Cup championship match between the Portland Timbers and Columbus Crew.

The league should give itself a good pat on the back because, when it began two decades ago, many observers and critics were ready to give it a nice, swift kick in the rear end and out the door because they didn't think the fledgling league would last even two seasons.

"We’ll celebrate the best of our league and the best of our sport at our Cup, and nothing is going to diminish our excitement with our 20th MLS Cup and the celebration of where we've been for the last 20 years," MLS commissioner Don Garber said during a state-of-the-league speech Thursday.

MLS survived its great purge back in 2002, when the league contracted from 12 to 10 teams, jettisoning under-performing Florida teams in Miami (actually, Fort Lauderdale) and Tampa.

It also survived the embarrassment, mismanagement and even the pro-Mexican racism of Chivas USA, whose Mexican owners sold the team back to the league after the 2014 season.

More On This...

Moreover, the league has thrived. It has blossomed from 10 teams in 2002 to 20 today. Thirteen soccer-specific stadiums have been built by the franchises, media revenues have grown and high-profile players have been lured from overseas while not losing sight of home-grown talent.

What’s more, league attendance has gone through the roof.

MLS teams averaged 21,574 spectators a match in 2015, an increase of 12.7 percent from 19,147 the previous season. The Seattle Sounders, who play at CenturyLink Field, home of the NFL's Seattle Seahawks, led all teams with an average gate of 44,247.

The league’s attendance was helped by two expansion teams that finished did not play in soccer-specific stadiums – Orlando City (32,847 per game) and New York FC (29,016), second and third in attendance behind Seattle.

The Colorado Rapids brought up the rear in attendance at 15,657, which not too long ago – 2006, to be precise – was right around the league average.

There is a lot to be proud of.

"We've been around for a generation. The brand is very simple. We are the league for a new America," Garber was quoted as saying by Reuters earlier this week. "A country that is changing, that has become increasing global.”

Garber added, "It has shifting demographics that has our nation looking like, acting like, we are a country represented by every country from around the world."

Those shifting demographics, not surprisingly, include a much larger Hispanic population by the middle of the century.

In fact, Garber wants MLS to become one of the great soccer leagues of the world by 2022 – quite a lofty goal. A decade ago, many soccer observers probably would have laughed him out of the room.

If the league aspires to orbit the same stratosphere as England’s Premier League, Spain's La Liga, Italy's Serie A and Germany's Bundesliga, its owners must open up their pocket books more by signing big-name players in their prime, not declining thirty-somethings.

In a giant step in that direction, the L.A. Galaxy earlier this year signed Mexican striker Giovani dos Santos, a standout who’s still in his prime. More players are expected to follow dos Santos.

“We have been going about building quality systematically, and I think that systematic, strategic approach has allowed us to be in the position that we’re in today, which is careful and controlled growth,” Garber said. “It started in 2007 with the need to bring in a bigger-name, more experienced international players that that led to the Designated Player rule.”

He went on, “At the bottom of the roster, and this has a lot to do with our relationship with the Canadian Soccer Association and U.S. Soccer. We needed to invest in youth development through a mandate with our academy program. Where we are now is focusing on the core of our rosters, the middle of our rosters, positions four through seven or eight.”

Despite the advances, there still are major challenges ahead.

No MLS team has won the CONCACAF Champions League, which Mexican teams have dominated. When the tournament resumes in February, four MLS teams will play Mexican foes in quarterfinals.

At that point, MLS teams will be in their preseason, while Liga MX clubs will be in the middle of theirs and in top form. The league and its teams must find a way to get over that hump.

MLS plans to expand to 24 teams. Atlanta will kick off play in 2017, followed by the Los Angeles Football Club, Chivas USA's successor, in 2018. Minneapolis-St. Paul also has been awarded a franchise.

The Miami team, whose ownership group is headed by David Beckham, was awarded a franchise that was contingent on finding a stadium. However, the group has experienced big headaches trying to find a stadium site.

NYC FC, which called Yankee Stadium home in this, its maiden season, could be there for quite some time to come while it seeks a new home in the confines of New York City.

In contrast, Maprfe Stadium in Columbus, Ohio -- the league’s first soccer-specific stadium built in 1999 – will be the venue for the MLS Cup on Sunday.

Columbus reached the Cup in 2008 and beat the Red Bulls for the league title. Portland has never made it this far before, but it has one of the league’s most rabid fan bases, ranking No. 4 in average attendance this season.

Both squads are in the middle of the pack in terms of player salaries and don't have a high profile international on the level of Orlando City's Kaká or NYC FC star trio of David Villa, Andreas Pirlo and Frank Lampard.

Columbus, in fact, changed its entire ticket sales focus between 2014 and 2015, to focus less on season-ticket sales and instead made playoff games its priority. This after a disastrous turnout of just 9,040 fans (less than half capacity) for its only 2014 playoff home game against the New England Revolution – which the Crew lost 4-2.

“When we closed 2014, we made it an overarching club goal to grow our playoff attendance,” Columbus president Andy Loughnane, told Sports Business Daily.

The Crew started having internal meetings in April to strategize, concluding that October was too late to make playoff tickets available to fans. This year, playoff tickets went on sale in August – the earliest in the league.

The result has been three sold out playoff matches – including the MLS Cup, tickets to which sold out in record time – regular-season attendance up 5 percent, merchandise sales increased by double digits, and even sponsorship revenue up 45 percent.

In many respects, the fact that relatively small-market teams like Portland and Columbus are among the league’s elite is thanks to the MLS’s single-entity concept, which doesn't allow teams to spend wildly beyond the salary cap and other restrictions.

“Every fan should believe that their team can win the MLS Cup,” Garber said. “It is not a league of haves and have-nots. That is something that is empowering to fans, and everyone around the league should feel good about it.”

And the league should feel pretty good about where it has been and where it is going as well.