Playing the first leg of its quarterfinal CCL tie against the Philadelphia Union at Mercedes-Benz Stadium Tuesday night, Atlanta United came out of the gates aggressive and plying some of its most attractive stuff of the season. But two simple mistakes, a poorly defended corner and miscue leading to a goal, and a some raggedy play late in the game gave Philadelphia a solid lead going into the second leg. It must be said that despite the scoreline, it was an impressive performance from the Five Stripes, who dominated the run of play most of the night.