Starting on the right side of midfield because Ben Olsen is injured, Devon McTavish scored twice to give him three goals in two games. Santino Quaranta, signed as a free agent in the offseason, celebrated his return to RFK Stadium, where he started his promising career as a teenager, by coming off the bench and helping set up the last three goals.
McTavish had not scored in his first two MLS seasons. Quaranta's once-promising MLS career looked to be over at the age of 23 when he was released by New York in January, but D.C. took another shot at the Baltimore product.
Brazilians Luciano Emilio and Fred accounted for the other three goals. Emilio started a three-goal run in five minutes in the second half with the first of his two goals.
The game marked the RFK debut of Argentine star Marcelo Gallardo, whose free kick set up McTavish for the lone first half goal.
D.C. United won, 6-0, on aggregate and advances to the semifinals against the winner of Wednesday's game between Mexico's Pachuca, the defending champion, and Honduran club Motagua.