Chris Rolfe nicked an 83rd-minute winner as DC United beat New England Revolution 2-1 at the RFK Stadium on Wednesday evening to book a date with New York Red Bulls in the Eastern Conference semis.
Only 15 minutes elapsed before the visitors moved ahead, with Juan Agudelo poking home from roughly 12 yards out following a cross from Kevin Alston.
DC very nearly moved level on 21 minutes when Fabian Espindola missed from close range after Bobby Shuttleworth palmed away Rolfe's speculative effort.
United continued to threaten, and they found the breakthrough in timely fashion as Chris Pontius headed home Espindola's delivery in the second minute of first-half stoppage time.
Jermaine Jones's long-range attempt on 56 minutes was as close as the visitors came to wresting back the lead in a second half which was dominated by DC.
They could, and should, have yielded tangible reward from their dominance with 15 minutes to go, but Rolfe crashed a penalty against the crossbar after Scott Caldwell handled Alvaro Saborio's shot.
Rolfe, United's leading scorer in 2015 with 10 goals, atoned for his error, with the veteran stroking home an Espindola cross as Ben Olsen's men planted one foot in the semis.
Any hopes of a comeback were effectively dashed late on when Jones saw red following a second booking as DC marched into the last four.
