Playing shorthanded the entire half, United seemed en route to a nervy victory before conceding three late goals and falling to Austin FC, 3-2.
Danny Hoesen (80th minute), Sebástian Driussi (85th) and Ruben Gabrielsen (first of eight minutes of stoppage time) turned certain defeat for the visitors (4-1-2) into an implausible victory.
The late uprising ended a nutty night that began with a 30-minute lightning delay and spoiled the MLS debuts of United’s Taxi Fountas, the club’s highest-paid player, and 17-year-old midfielder Jackson Hopkins, who signed a pro contract days earlier.
United busted out of a goal rut but lost its fourth straight.