THEY HAVE BEEN the Butler, Murray State and Virginia Commonwealth of the U.S. Open Cup.

Just as those schools have knocked off bigger college programs in the NCAA men's basketball tournament, Harrisburg has advanced in American soccer's version of March Madness. In the winner-takes-all format of the U.S. Open Cup, the City Islanders have been Cinderella, knocking off a pair of MLS teams to make the quarterfinals — New England and New York; the former saw Harrisburg come from 3-0 down to win in penalties.

Now it's the Union's turn to try to buck the trend — against its minor league affiliate — or, become another club Harrisburg checks off its list in a quest to become the first USL Pro team to capture an Open Cup crown since Rochester in 1999.

"We are taking this tournament very seriously and we know they are, too," Union midfielder Jack McInerney said. "But this is a chance for us to get our first trophy and with the season we've had, it would be a great way for all of us to continue to build confidence."

The Union made the quarterfinals after a 2-1 win over D.C. United in added time in fourth round play. If the Union beats the City Islanders, it will host the winner of MLS team Sporting Kansas City vs. a USL Pro squad, the Dayton Dutch Lions, on July 10 or 11.

"They have a really good team, and we know them very well," defender Gabe Farfan said of Harrisburg. "They have a lot of talent. Harrisburg is a team we can't take for granted; we saw what they've done against better clubs. We'll have to put forth our best effort for 90 minutes."

The last time these two faced each other, Harrisburg defeated a reserve-heavy Union side, 3-2 in a friendly at Hersheypark Stadium. It's a moment that former Union midfielder Morgan Langley, now with Harrisburg, hasn't forgotten. Langley, who appeared in only one match with the Union last season, is eager to show in a game that matters exactly what he's worth.

"I'm not gonna lie, I absolutely do have a chip on my shoulder," Langley told the Union's website. "I believe that I can be at that [MLS] level. I just believe that I need time to develop, and I'm very happy where I am right now. I think I've developed a lot here. I'm ready to go and show the fans that I've developed and I'll continue to develop over the next couple of years."

And while City Islanders midfielder J.T. Noone said he's treating this match the same as any other, the Union, knowing what's at stake, certainly is not.

"We can't take Harrisburg lightly on Tuesday," said defender Ray Gaddis, who spent time last season with the Union's other minor league affiliate, Reading United. "We are excited about our win against Sporting Kansas City [4-0 on Saturday], but now it's back to business." n

Contact Kerith Gabriel at Follow him on Twitter @sprtswtr.