Every D.C. United match these days carries the weight of mandatory points. The margin of error to qualify for the MLS playoffs is paper-thin and, on those occasions when a deficit smacks Coach Ben Olsen’s gang in the face, the remainder of the game turns into a test of character.

Sunday’s date with the Chicago Fire also pressed United’s patience: There was a disallowed early goal, a deficit shortly after halftime and a generally imperfect performance that injected a wave of nervous energy throughout sun-splashed Audi Field.

But United is also playing with the type of belief that conquers such predicaments, and on an unseasonably hot day at Buzzard Point, Wayne Rooney scored twice in a 19-minute span of the second half for a 2-1 victory.

Unbeaten in six straight, D.C. (11-11-8) pulled back within two points of Montreal in the mad scramble for the Eastern Conference’s last playoff spot.

United has played two fewer games than the Impact, and by beating Western-leading FC Dallas and Toronto FC before Montreal plays again, D.C. could take control of the race entering the last two weekends of the season.

“We just have to keep pushing,” Olsen said. “We have another most-important-game-of-the-season next weekend. That’s how it’s going to roll the rest of the year. That’s okay. I trust our guys are up for it.

“We didn’t have the greatest performance today, but there is a belief in the group that on days like this, we can still get three points.”

Chicago (8-17-7) went ahead in the 51st minute on Raheem Edwards’s goal, but Rooney scored the equalizer in the 62nd and converted a penalty kick in the 81st before an announced sellout of 20,064.

It was not easy, by any means.

“These are games we have to win,” said Rooney, who has posted six goals and four assists in this unbeaten run and nine goals and seven assists in 16 appearances since debuting in mid-July. “Sometimes when you are not your best, you need to make sure you get something out of the game.”

Like the second half itself, the go-ahead goal was also full of tension. After Johan Kappelhof knocked down Junior Moreno from behind in the box, Rooney stepped to the penalty spot. Failure here would have surely deflated the hosts, especially after Rooney had squandered a partial breakaway moments earlier.

Facing Stefan Cleveland, a goalkeeper who was playing college soccer two years ago and making his fifth MLS start, Manchester United’s all-time scoring leader ripped his attempt beyond Cleveland’s reach and into the left corner.

The deficit hadn’t seemed to faze United, and with Rooney on the prowl, D.C. executed its second comeback victory in four matches.

“The good thing is we’ve been on a good streak and [have] the confidence to know that anytime we will be able to change the game,” said Paul Arriola, a midfielder who played right back in place of injured Oniel Fisher. “It could take one guy. Today Wayne was able to put two away. But the PK isn’t about us; it’s about the man stepping up and finishing the game off. That’s what we’ve been lacking, and now look at us.”

There wasn’t a lot to see for much of the afternoon. United appeared to break the deadlock in the 22nd minute when Rooney began and finished a counterattack. But in the final buildup, Luciano Acosta had tripped a defender, an act that freed him up to supply Rooney. Referee Ismail Elfath consulted video replay and annulled the goal.

“It was probably something that didn’t need to come back,” Olsen said. “If we had lost, I’d probably be less calm about it.”

United was faulty with its finishing: Yamil Asad missed the short side from 10 yards and Ulises Segura rattled the crossbar from six yards.

The disallowed goal and misses were costly as Chicago went ahead. Aleksandar Katai collected the ball at midfield and rushed into open space before connecting with Edwards, whose cutbacks sent Frederick Brillant and Russell Canouse to the turf and provided ample time to beat Bill Hamid from 10 yards.

“The goal,” Rooney said, “woke us up a little bit.”

United pulled even, though the players and supporters had to hold their collective breath for a moment because Rooney was close to being offside.

As Rooney made his run in the box, Arriola crossed behind the defense. Cleveland made a reflex save on Rooney’s redirect, but the rebound returned to the D.C. striker for an easy deposit. This time, the goal stood.

“I didn’t know [Rooney] scored the first one,” Olsen said. “I thought it was [Canouse]. Someone just told me he scored that one too. He is chipping in.”

To say the least.

Rooney’s expert finish on the penalty kick eased the late-game pressure and provided a clearer path to the playoffs.

“We had to win this game, just like we have to win every game,” Acosta said. “We all had to stay calm and find a way to turn the result around.”

United notes: Defender Nick DeLeon, sidelined almost 4 1/2 months with a knee injury, entered in the 87th minute . . . Segura (Costa Rica), Moreno (Venezuela) and Darren Mattocks and Dane Kelly (both Jamaica) will join their respective national teams Monday and miss Saturday’s MLS match against Dallas.