In just its third MLS season, Atlanta United beat the USL's Charleston Battery 3-1 and then knocked off the MLS' Columbus Crew 3-2 in a downpour to earn its spot in Wednesday's quarterfinals. Last December, Atlanta United defeated the Portland Timbers 2-0 at Mercedes-Benz Stadium in Atlanta to win the MLS Cup.

“We're going in to play in a really great environment against a really, really good team,'' STLFC's Russell Cicerone said. “It's going to put our group to the test, but I have all the faith in the world that we're capable of handling it.”

Added STLFC's Kyle Greig: “It's a big opportunity for us, going in as underdogs.”

Atlanta United is 9-7-3 and in third place in the MLS' Eastern Division. They are led by reigning league MVP Josef Martinez, who has 12 goals and two assists this season. Other top scorers are Ezequiel Barco (four goals, one assist) and Julian Gressel (three goals, three assists). Other players to watch are goalkeeper Brad Guzan, defender Leandro Gonzalez Perez and and midfield leader Darlington Nagbe.