The U.S. Open Cup, the oldest continuous soccer tournament in the United States, kicked off its 102nd year last week, and it's something soccer fans in the United States really should be paying attention to.

Real Monarchs have their berth into the tournament on Wednesday with a second-round match against Long Island Rough Riders, while Real Salt Lake will play in June against a to-be-determined opponent.

It's the oldest continuous soccer tournament in the United States

The U.S. Open Cup has been organized since 1914, making 2015 its 102nd year of being contested. It's not quite as old as England's FA Cup, which started in 1871, but as far as American soccer is concerned, it's as old as it gets. Originally known as the National Challenge Cup, it became the Open Cup in 1990, then the Lamar Hunt U.S. Open Cup in 1999 in honor of one of the original investors in Major League Soccer.

The winners represent a diverse outlay of American soccer history

From five-time winners Bethlehem Steel and Maccabi Los Angeles, both defunct, to four-time winners Chicago Fire and Seattle Sounders, both still around in MLS, the list of U.S. Open Cup winners offers a long look at the history of the sport in the United States. Following through the list of winners introduces readers to the American Soccer League, the National Association Football League, the NASL that ran from 1968 to 1984, and to a variety of amateur organizations and teams.

The Cup represents huge pieces of American soccer history that are not just easy to ignore — they're difficult to find and uncover.

It hasn't been won by a team in Utah — yet

Real Salt Lake had the best opportunity to win the trophy in 2013, when the final was hosted at Rio Tinto Stadium against D.C. United, but some poor play and D.C. heroics sent RSL spiraling. That leaves both Real Salt Lake and Real Monarchs with a chance to make the first Utah mark on the trophy this year.

It spans every level of professional and amateur organized soccer

While a team outside MLS hasn't won the US Open Cup since 1999, when Rochester Rhinos, then in the USL A-League, won the Cup, you can still find teams from every level of U.S. soccer involved. Amateurs like Harpo's FC, which beat BYU last week, and Cal FC, which made a deep run in 2012 and made the first round this year, represent the diversity of the competition. Harpo's, of the United States Specialty Sports Association, and Cal FC, of the United States Adult Soccer Association, are this year's representatives of what's called “non-league” soccer — they exist outside the auspices of the top three or four divisions of professional soccer.

Matchups you'd never see anywhere else

In no other American soccer competition are you likely to see a brewery team, Harpo's FC, face BYU — or an amateur side like Cal FC running through the competition and hitting the fourth round. The intrigue around an unknown opposition is palpable. It's infrequent that teams from the several leagues across the United States play each other, and the Cup provides an opportunity to see that.

The emergence of giant-slayers

In few other American competitions does one get to see amateurs with day jobs square up against well-paid professionals, and while the ones you'd expect to win typically do, every year, a big team comes up against a smaller team and walks away shocked and disappointed.

Matt Montgomery is the managing editor of RSL Soapbox.

Twitter: TheCrossbarRSL