Hackworth continued to profess confidence in the team, but he acknowledged how difficult this has been.
"As coaches, players, our whole staff, our organization is definitely frustrated," Hackworth said. "I don't know how to put it any other way."
D.C. United, which won three games all last season, is 4-3-2.
In the sixth minute, Rolfe, who was acquired April 2 from the Chicago Fire, received a deflected cross from Cristian Fernandez. Standing at the penalty-kick area 12 yards out, an unmarked Rolfe made a chest trap and fired a volley past Zac MacMath, a shot the Union keeper had no realistic chance to save.
After a sluggish first half in which the Union had no major scoring opportunities, they began taking it to United and controlling play in the second half.
In the 64th minute, the Union had their best chance - actually, three of them, inside the box. United keeper Bill Hamid stoned Andrew Wenger dribbling in on goal. Hamid somehow got a piece of Conor Casey's rebound, and then United midfielder Perry Kitchen deflected an attempt from a charging Danny Cruz.
"We had three guys, including myself, who had a chance to get it in. It just didn't cross the line," said Cruz, who replaced Brian Carroll to begin the second half after Carroll tweaked his groin. "There are guys laying their bodies out and giving everything they have, and we hope it gets going soon."
One of the Union's problems is an inability to take on defenders one-on-one. In the first half, their best attackers were outside backs Fabinho and Ray Gaddis.
"Today they were a little predictable and made it a little easier in the back, knowing they were going to whip crosses in," said former Union defender Jeff Parke, now anchoring United's defense. "That being said, they had the ball the majority of the second half and are still a really good team."