Having already reached the final stages of the competition during its early years in 1948 and 1949, the Eagles reached the semifinals in 1989, losing on penalties to eventual winners St. Petersburg Kickers, and won the tournament in 1990 in the pre-MLS era, beating the Brooklyn Italians 2–0 in the final thanks to goals from Janusz Kieca and Peter Modrzejewski.

Their win in the competition also gave them entry to the 1991 CONCACAF Champions' Cup, where they lost 4–1 on aggregate in the first round to Bermudian club PHC Zebras.

The Eagles qualified for the cup again in 1994, the last all-amateur competition prior to the entrance of teams from Major League Soccer, but lost 2–1 to Bavarian Leinenkugel in the quarterfinals.

[2] In 2008 the club qualified for their fourth modern U.S. Open Cup, beating the Milwaukee Bavarians and Des Moines Menace Reserves in their regional qualification tournament,[3] but lost 4–0 in the first round to the Pittsburgh Riverhounds of the USL Second Division.

Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.