By the 72nd minute Saturday night, groups of spectators stood and threw their arms in the air. It caught on. Within a minute or two, a full-on wave spread across every section of Audi Field. Young girls, clad in jerseys ranging from Megan Rapinoe to Alex Morgan to Rose Lavelle, screamed and waved their arms. A “Let’s go, Spirit!” chant followed.

Then another group of fans, mostly in Section 117, started a yell of their own. They grew louder, and finally they were discernible, loud and clear. “Equal pay!” they yelled. “Equal pay!”

The crowd of 19,871, a record for a Washington Spirit game, had assembled at Audi Field, and here they were: cheering, chanting and supporting the U.S. women’s soccer team’s fight for equal pay. By the time the chant broke out, the Spirit had a 2-1 lead it wouldn’t relinquish to the ­Orlando Pride.

It was a remarkable sign of growth for an organization without a winning tradition that plays most of its home matches at a small complex 17 miles outside the Beltway.

“Fantastic atmosphere,” Spirit Coach Richie Burke said. “I just hope we were able to inspire the next Rose Lavelle, Mallory Pugh, Andi Sullivan in the crowd watching us play tonight.”

Washington played at Audi Field once late last season, drawing a record 7,976 spectators. This time, the club more than doubled that, the attendance nearly six times the Spirit’s average this season.

As for the soccer, Lavelle, Pugh and Orlando’s Alex Morgan did not play because of injuries. But there was a lot at stake for Washington, which needed to jump on the opportunity at home to pick up ground in the standings. The Orlando Pride (4-12-2) entered the day in eighth place in the nine-team National Women’s Soccer League. The Spirit (7-7-4) remains in sixth place — eight points back of first-place Portland.

The scoring started early, with the Spirit delivering in the ninth minute. Forward Crystal Thomas, a Georgetown graduate, pounced on a mistake by Pride goalkeeper Ashlyn Harris for a 1-0 lead. Thousands of fans erupted in unison, and a “D.C.!” chant began.

Orlando responded in the 31st minute with a goal from Marta. The Brazilian national team forward — who has a record 17 goals at World Cup tournaments — found the left corner of the net to even the score.

Washington broke the deadlock in the 59th minute when Spirit defender Tori Huster struck a ball to the goal area, where forward Ashley Hatch delivered a header into the back of the net. Hatch, wearing a wide smile, ran over to hug Burke on the Spirit sideline. He clenched his fists, and then he lifted up Hatch.

“A goal scorer’s dream,” Hatch said of the moment.

The crowd was a factor all night, with fans flocking to the home of D.C. United to see the stars from the Women’s World Cup — even though some did not put on a uniform.

“[Audi Field] is even better in person,” said Arpita Venkatesh, 26, who attended Saturday’s game with a friend. “Now we know what we’re fighting for: them to get to play here all the time.”

Spirit owner Steve Baldwin will assess Saturday’s turnout and revenue, as well as the game’s effect on the bottom line. He will do the same in three weeks — after another expected sellout Sept. 14 vs. Reign FC — by weighing the benefits of playing in D.C. vs. expanding its fan base with the cost of renting Audi Field and alienating suburban ticket holders.

While Baldwin’s plans are uncertain at this point, the record crowd may not be an anomaly. It suggests there’s a market for professional women’s soccer ­beyond minor league-size fields. Earlier this month, 25,218 fans packed Providence Park in Portland, Ore., where the Thorns set the all-time NWSL attendance record.

On Saturday, the Spirit filled Audi Field, even on a night when three of the sport’s biggest stars didn’t play.

“We’re proud to be your team,” Burke told the crowd at the end of the night. “From the bottom of our heart, you’re our 12th man. Thank you, thank you, thank you!”

Then he passed the microphone to Baldwin.

“Tonight,” he said, “is about celebrating the excellence of women’s soccer this decade.”

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