WASHINGTON, D.C. -- Penalty kicks made all the difference for D.C. United on Saturday night -- the two they conceded made for the only goals in their losing 2-0 home match vs. Columbus Crew SC. And as it turns out, one of those should never have happened at all, according to DCU's head coach.

“First one, I think, is probably a good call,” said Ben Olsen of the penalties. “The second one was a terrible call. I am pretty sure on both of those, and I think referees should be pretty sure on calling PKs.”

In the 37th minute, Columbus striker Ola Kamara received a short pass inside the 18-yard box, only for D.C. defender Steve Birnbaum to knock him down. Immediately, Birnbaum threw his hands in the air in protest, but referee Ted Unkel called for the spot kick. Columbus midfielder Federico Higuain put the kick low and to the bottom left corner, past a diving D.C. goalkeeper Bill Hamid.

“We didn’t have very many calls our way,” Birnbaum said after the match. “Not happy about it. It was tough night.”

United strung together a series of unsuccessful attacks on Columbus’ defense and their goalkeeper, Zack Steffen. And despite playmaker Luciano Acosta's return, they repeatedly failed to finish.

“It is finishing. If we were not creating, I would be worrying, but we are creating a decent amount of chances,” D.C. midfielder Patrick Nyarko said. “Today the goalie [Steffen] made some unbelievable saves to keep us out. But those things will correct itself.”

D.C. substitution Jose Ortiz, who entered the game in the 28th minute for an injured Patrick Mullins, provided one of United’s closest chances on the night. He laid the ball off to Lloyd Sam inside the box, and on a back-heeled pass from Sam, Ortiz dribbled into Steffen.

“I didn’t think it was a terrible performance from either side,” Olsen said of his team's showing. “Overall it was a step in the right direction. It was good to see Lucho back out there. Some good performance, but not enough good performances.”

The final goal of the match came in the 66th minute with a little deja vu. Once again, Unkel whistled Birnbaum for a reckless challenge on Kamara inside the box. This time, though, it was Kamara who scored the penalty against Hamid, with the goalkeeper once again guessing correctly and diving the right way. Both Birnbaum and Olsen disputed the penalty call after the game.

There was no explanation for either call after the game, Birnbaum said.

“[Unkel] didn’t say anything,” he said. “I thought we were shoulder-to-shoulder in the box. I thought I had a good angle. I don’t know what to say. I didn’t think it was a penalty, but it is what it is.”

United has dropped three games to start the 2017 season, and is goalless in 270 minutes of play.

“It is frustrating,” defender Taylor Kemp said. “You can’t win if you don’t score, but I do think this was a better performance from us as a group.”