The Union survived the inclement weather, a red card and one of their shots that hit both posts. Neither the elements nor some flat-out bad luck could stop them from defeating D.C. United, 2-1, in a U.S. Open Cup round of 16 game Tuesday night at PPL Park.

Fabinho converted an excellent give-and-go from Cristian Maidana in the 80th minute for the winning goal.

The Union will meet the winner of Wednesday's game between the New York Red Bulls and New York Cosmos in a quarterfinal on July 21 or 22.

In the 56th minute, the Union tied the score when Maidana found Sheanon Williams. With a cross from near the left end line, Williams hit a wide open Erik Ayuk, who tipped in the equalizer.

That came shortly after the Union's Andrew Wenger hit both posts on a shot.

D.C. United were playing with a majority of reserves because the team has an MLS game on Friday in Seattle. That said, the Union were playing shorthanded from the 25th minute on after C.J. Sapong received a red card after going up for a head ball with Kofi Opare.

"I thought our group took a big step tonight, and in a lot of ways it is the most proud I am since I have been the head coach because games like this bring groups together," Union coach Jim Curtin said.

Sapong and the PPL Park crowd were shocked to see a red card. Apparently he was called for elbowing Opare.

Curtin said he didn't receive an explanation from the referee.

"The call was a mistake," Curtin said. "He doesn't extend the elbow, he jumps as high as he could, and it wasn't malicious."

With the game scoreless in the 15th minute, lightning forced a 46-minute delay.

In the 27th minute, United opened the scoring when Jairo Arrieta tapped in a loose ball in front of the goal that keeper John McCarthy had no chance at saving. McCarthy, who earned the start over Andre Blake, was solid in goal.

Despite that goal, the Union controlled play for much of the time they were a man down.