D.C. United’s 3-1 victory over the New England Revolution on Wednesday night at Maryland SoccerPlex booked a place in the U.S. Open Cup semifinals. To Coach Ben Olsen’s approval, the result also kept United on a positive trajectory after a ruinous first half of the regular season.

Although the MLS playoffs remain a distant possibility, United is playing competently. And with Dwayne De Rosario staying on scoring pace in the 100th annual tournament with a tiebreaking goal in the 69th minute, United advanced to face MLS’s Chicago Fire on Aug. 7 at Toyota Park.

“Mostly I am excited about the last couple weeks,” Olsen said of his team’s 3-1-1 run across all competitions. “We have seen it moving in the right direction. These guys deserve a little bit of joy right now. It’s been a tough grind.”

United has scored just eight goals in 16 regular season matches but six in the past two Open Cup games against MLS opponents. The club also has created a stream of quality opportunities in the tournament — something it has labored to accomplish with any frequency in league play.

“It shows the quality we have, but I would like to see that in the [regular] season,” said De Rosario, who recorded a hat trick against Philadelphia two weeks ago in the round of 16. “Like I told these guys, ‘Let’s keep moving forward. Don’t look back.’ ”

In front of 2,918, Chris Pontius capped a well-crafted sequence that began in the back in the 44th minute. Conor Shanosky picked out Pontius, who led Nick DeLeon on the right wing. DeLeon’s cross was deflected to Pontius, who turned at the top of the box and pinpointed a low shot beyond Matt Reis’s dive.

New England drew even eight minutes after intermission. Joe Willis got a hand on Juan Toja’s wicked free kick, but the velocity sent it smashing off the crossbar, then off the goalkeeper’s back before settling into the net. Toja was credited with the goal.

New England continued to dictate terms. “I was a little worried,” Olsen said. “The response wasn’t great after the goal.”

Midway through the half, however, Pontius targeted De Rosario with a long corner kick. Over a decade of excellence, De Rosario has done his masterwork with his feet, not his head. This header was angled, from distance and without great pace. But De Rosario placed it perfectly, arching the ball over Reis.

After Pontius failed to pick out De Rosario on previous set pieces, “I said, ‘Listen, look for me [at the] back post.’ He played a good ball,” the captain said.

Although De Rosario is not a heading expert, “I have confidence in Dwayne scoring because he has done that a lot in his career,” Pontius said.

After New England’s Juan Agudelo hit the left post from 18 yards, United substitute Lionard Pajoy sealed the outcome by drawing and then converting a penalty kick with about four minutes left.

United notes: In a move anticipated for several days, the club released Brazilian forward Rafael, opening an international roster slot and salary cap space. He made seven appearances (four starts) and scored once but played in just two of the previous seven regular season games. The club plans to sign two or three players soon. . . .

Goalkeeper Bill Hamid was called up to the U.S. national team for the CONCACAF Gold Cup, sources said. He will miss up to a month of MLS play.