David Perez, (left) of Culpeper, and Josh Stendeback, (right) of Arlington, camped out in front of Capital One Arena starting early Thursday morning. (Jacob Bogage/The Washington Post)

Washingtonians have waited more than a quarter-century for a championship from one of the country’s “big four” professional leagues. Capitals fans have waited four decades for their first Stanley Cup. Both droughts could end Thursday, a realization that was abundantly clear to the thousands of red-clad faithful who ringed Capital One Arena hours before the puck dropped at Game 5 of the Stanley Cup finals — in Las Vegas.

They were there, at first, for a WNBA game between the Washington Mystics and Minnesota Lynx. The league bumped the game time up, from 7 to 4 p.m., to make way for a Capitals watch party. The result was a rush on Mystics tickets, which guaranteed fans admission to the party that would immediately follow the game.

It touched off as near a festival of local sports as the District has seen in a generation. With police cordoning off a city block around the arena, fans gathered starting in the early afternoon to wait out the moments until the arena doors opened, spending the time until then reveling in Washington’s athletic success.

“I remember the Redskins’ championship [in 1992], but I wasn’t part of it. I was a kid,” said Josh Stendeback, 33, of Arlington. “I want to be part of this.”

Stendeback arrived at Capital One Arena’s F Street entrance at 8:50 a.m., with a lawn chair, two laptops (in case he couldn’t access a power outlet), a Nationals hat and an Evgeny Kuznetsov jersey. He launched a wireless hotspot from his phone and put in a full day’s work, he said: “My inbox is empty.”

Fellow Capitals fans greeted him all day with cheers. He said that Metro riders from the Gallery Place station asked him how long he’d been waiting. He made friends with the NBC Sports television technicians setting up their broadcast in the middle of the street. Police officers came up to snap pictures and shake hands.

“People love to see people celebrating,” he said.

At 9:15 a.m., David Perez arrived from Culpeper with a lawn chair wearing a Capitals hat and an Alex Ovechkin jersey. He set the chair down next to Stendeback.

“I told my family, ‘The Cup is going to be won tonight,’ ” Perez said, predicting a 3-1 Capitals win. “ ‘I have to be there.’ ”

So did Andria Arnold, who arrived at 2 p.m. She held a sign declaring she had traveled 4,000 miles to be home for the game.

The Calvert County native flew home from Madrid, where she teaches English by day and watches Capitals games online in the middle of the night.

“I’d show up to work with zero sleep but happy that we won,” she said of Washington’s playoff run while standing in line at the Sixth Street arena entrance. It snaked around the corner onto G Street, where fans in both lines exchanged chants of “C-A-P-S! Caps! Caps! Caps!” and “We want the Cup!”

When Washington beat Pittsburgh in the second round of the playoffs, Arnold started looking at prices for flights home. When the Caps beat Tampa Bay in the Eastern Conference finals, she booked her plans. Family friends heard she was on the way home and bought her a Mystics ticket so she wouldn’t miss the watch party.

“I always knew if something happened in the playoffs, and I made it home to D.C., I’d be here,” she said.

With careful coordination, Mystics event staff opened the arena gates at 3 p.m. Staffers in head-to-toe red stood behind ticket-takers handing out red rally towels that read, “Rock the red in ALL CAPS.” Security guards called after fans in Capitals jerseys to walk, not run, to their seats.

“I expected it to be a zoo,” Mystics season ticket holder Sandy Seim said while speed-walking to her seat. “I just hope all the Caps fans yell like crazy for the Mystics.”

They did.

Sections in the lower bowl around the court filled up quickly as Washington hung with Minnesota, the defending WNBA champion. By the second half, sections behind each basket were occupied.

In the fourth quarter, event staff opened the upper deck to newcomers and, as the Mystics tried to mount a comeback, Slapshot, the Capitals’ mascot, presented Pax the Panda, the Mystics’ mascot, with a hockey jersey. It didn’t help; the Mystics lost, 88-80.

The jumbotron played Capitals’ playoff highlights and the public address announcer implored fans, certainly more than the 8,587 announced attendance, to wave their towels and scream.

They obliged.

“Today,” Arnold said, “I’m a Mystics fan.”

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