With scoring opportunities and goals in short supply this season, D.C. United Coach Ben Olsen figured, as a starting point, he could count on his defense to grind out results until the attack caught up.

On Saturday, both aspects let him down.

The attack was typically unfulfilling and the defense was atypically second rate, a lethal brew resulting in a 2-0 defeat to the New York Red Bulls at Audi Field.

Aaron Long was left open on a free kick in the first half.

“Really poor,” Olsen said.

Daniel Royer took advantage of Donovan Pines’s missed header in the second half.

“Another poor defensive play,” Olsen said.

United (2-5-4) was markedly better in the attack than last week, when it had no shots, no corner kicks and no quality possession in a scoreless draw with New York City FC. But it failed to put away multiple first-half opportunities before fading after intermission.

In the past seven games, United has gone scoreless four times and scored once in each of the others.

At home this year, United is 1-3-1 with four goals — one in the past three outings.

Olsen noted the improved attack, but, he added, “still a little anemic in the final third” of the field. “Once again, we just didn’t reward ourselves.”

His team, he said, needs to become “a little more scary on offense.”

The outcome ended a four-game winless streak for the Red Bulls (4-5-2), who, after a 1-0 home defeat to United on Sept. 2, replaced coach Chris Armas with assistant Bradley Carnell. Saturday’s scoring output matched their total from the previous seven games.

Asked about the feeling among the players, D.C. defender Frédéric Brillant said, “Like you can’t imagine. It’s tough right now. The last two games we didn’t enjoy. We defend very hard [against NYCFC], and we get a point. We wanted to add something today. It was more enjoyable, but in the end, we have nothing.”

Amid a flurry of absences, Olsen’s search for the right lineup continued. He played with two strikers instead of one and four defenders instead of three.

Goalkeeper Bill Hamid was in uniform after missing three matches for personal reasons and fitness issues, but Chris Seitz (two straight shutouts) started again.

Venezuelan forward Gelmin Rivas made his first start, pairing with Ola Kamara. The double-striker formation bumped the skilled Yamil Asad from the lineup after he started six of the previous seven matches.

Kevin Paredes, 17, made his sixth consecutive start on the left wing, and Julian Gressel lined up on the right, though both pinched inside in an effort to stimulate the attack.

Right back Chris Odoi-Atsem made his first start since the final group match at the Disney World tournament in July, joining Pines, Brillant and Joseph Mora on the back line.

United set the tone, but without a true ringleader, the Red Bulls calmly absorbed early pressure.

Since the regular season restarted, set pieces have bedeviled United. It happened again Saturday.

In the 29th minute, Alejandro “Kaku” Gamarra served a 30-yard free kick deep into the penalty area. Long pulled away from Odoi-Atsem, and when neither Brillant nor Gressel picked him up, the center back stung a running header into the near side to end the Red Bulls’ scoreless streak at 263 minutes.

United generated two wonderful chances in the 37th minute, both involving Gressel and Rivas. Ryan Meara made a foot save on Gressel’s stab (a play set up by Rivas’s cross), then made a reflex stop on Rivas’s powerful side volley off Gressel’s corner kick.

The second half was not going much better. Olsen turned to his bench. Before Oniel Fisher and Erik Sorga could enter, though, the Red Bulls scored again, in the 60th minute.

Jason Pendant crossed from the left side. The ball floated over the leaping Brillant. Júnior Moreno backed off when Pines tried to head it. He did not make contact, allowing Royer to smash in a 10-yard volley.

“We have got the numbers to deal with the service,” Olsen said, “and we don’t deal with it.”

Three additional changes did not help United’s cause.

Amid the lackluster performances, “You are always taking that temperature” of the locker room, Olsen said. “But I’ve been around enough to hopefully keep the morale somewhat high. It’s okay if we’re pissed off and we’re upset because we’re not in a great spot right now.”

Notes: United will begin the second phase of the in-market schedule next Saturday against visiting Toronto FC. … Defender Steven Birnbaum, midfielder-defender Russell Canouse and attacker Edison Flores remained out with injuries.

Read more on D.C. United: