WASHINGTON—If the first round of the 2015 MLS Playoffs was all about early goals and open play, Bill Hamid was keen on establishing the Conference Semifinals as the round of the goalie.

But Dax McCarty and the New York Red Bulls were keen to prevent the first goalless game of the postseason.

New York Red Bulls captain Dax McCarty’s falling header in the second half gave the Red Bulls a vital away goal in their cagey 1-0 win over D.C. United Sunday afternoon in the nation’s capital. The Red Bulls will carry their advantage back to Red Bull Arena for the second leg of the series next weekend.

“I think any time you beat your biggest rival on their home field is significant,” McCarty said. “We feel good with this performance but…We realize D.C. is a good team…They’re going to come back and give us one of the toughest games we’ve ever had at Red Bull Arena.”

The game looked to be defined by the heroics of D.C. United goalkeeper Bill Hamid, who had eight saves in the match, until the 72^nd minute, when Red Bulls captain Dax McCarty got on the end of a long free kick cross by Sacha Kljestan. McCarty had beaten his marker along the back post, and his powerful falling header left Hamid with no chance to make another save.

“It felt good to get the goal,” McCarty said. “I felt like we were knocking at the door the entire game.”

“For a little guy, [McCarty has] great timing,” Kljestan said. “And a great attitude going into the box. [McCarty] made a great run.”

While not the goal-fest the early round playoff games were, the first half did see chances by both teams. D.C. United came out of gate seeking an early goal to set the tone of the series, but despite the onslaught of the first five minutes, the home team couldn’t find a goal.

Play opened up for both teams as the first half wore on. Squandered chances by Felipe Martins and Alvaro Saborio could have had either team take an early advantage, but the best chance of the first half went to the Red Bulls and Mike Grella, who found himself in a one-on-one with D.C. United goalkeeper Bill Hamid thanks to an erroneous clearance by Sean Franklin. Hamid saved face for D.C. United by blocking the shot off his face.

D.C. United manager Ben Olsen was left to rue the few chances his team had in the first half.

“We failed to win the set piece battle today, which was a big part of the game,” Olsen said.

Play resumed in the second half with the New York Red Bulls showing their intent early. A wild two minutes of action starting in the 58^th minute saw Hamid keep his team level with a diving one-handed save and relying on his near post to bail him out after Kemar Lawrence’s blistering attempt from a difficult angle after being released on an overlap.

Olsen said the Red Bulls’ first-round bye was a key difference in the second half.

“In the second half, you saw which team had been off for a week—and which team has been grinding for the last ten days,” Olsen said.

Referee controversy reared its head for the second time in two games at RFK in the 68^th minute, as New York Red Bulls defender Ronald Zubar left his feet in a late challenge on Markus Halsti near the corner of the box. After long discussions with representatives from both sides, referee Fotis Bazakos saw a yellow card was a deserved punishment.

“It has all the ingredients as to what they’ve been saying is a red card in this league,” Olsen said of the foul. “But that doesn’t matter all the time.”

D.C. United entered the game on a high after their midweek victory at home against the New England Revolution in the first round of the 2015 MLS Playoffs, while the New York Red Bulls enjoyed the fruits of a successful regular season, in which they finished first overall in MLS, winning the Supporters Shield.

But D.C. United were dealt a blow in the lead up to Sunday’s game when it was announced that team captain Bobby Boswell would serve a one-game suspension for his actions in D.C. United’s midweek game. The suspension is believed to be for a purposeful knee into the back of Revolution striker Juan Agudelo in the second half of the win.

The result means that D.C. United must now attack the second leg from the outset—something they’re not used to. The Red Bulls will look to keep the game as low-scoring as possible, relying on Luis Robles and the back four to lead the way to the Eastern Conference Finals.

Both teams stressed that there was still much to play for in the second leg.

“The job’s only half-done,” Red Bulls manager Jesse Marsch said.

“We’re disappointed,” Olsen said. “But optimistic that this is a series we can win.”

The teams will return to Red Bull Arena for the second leg of the series next Sunday, Nov. 8.