At left, Paul Pierce leaves the court after his game-tying three-pointer was ruled to have come after the final buzzer, ending the Wizards’ season. At right, the series-ending goal by the New York Rangers gets past Braden Holtby, who starred in one of the NHL’s great goaltending duels. ((LEFT) Jonathan Newton, (RIGHT) Toni L. Sandys/The Washington Post)

Paul Pierce may not know it, but he taught an entire city what professional sports is, why it hurts so much and how magnetic it is for those who truly commit to the experience, including fans who board a ship that usually ends up wrecked.

The only thing Pierce didn’t teach Washington this month is what it feels like to be a champion, to have the parade, to wear the ring. But he showed one of the keys to that eventuality.

Pros, the best and the most respected of them, talk about “losing hard.” It is an expression, written on faces in defeat, that can’t be defined, but can’t be missed either, or forgotten once it’s been seen. Few ever wear it. Many athletes, perhaps even most of them, deep down don’t even want to own that look.

Pierce wore the hard-loser look on Friday after the Washington Wizards’ season-ending, 94-91 loss to the Atlanta Hawks in Game 6 of their National Basketball Association second-round playoff series. His three-point basket, launched with his heels barely inside the sideline in the corner, saved a season — for perhaps three minutes. Until officials, and instant replay, decided that the ball was still, barely, grazing his fingertips as the clock, and the Wizards’ season, hit 0:00.

Yet losing hard is among the secrets to getting a ring. The cost is so extreme few want to pay it. Even Pierce, an exemplar of the type and a certain Hall of Famer, only has one title to show for 17 years of trying. Perhaps, for most people, it is not even a wise trade.

Now that Washington, and all the athletes on all the teams in town, have seen The Truth, it’s going to be hard to forget him. Or duck his oh-so-tough message.

Pierce is like a character in a medieval passion play who carries a sign that identifies the central quality he represents. Pierce personified what it means to care, give and risk so much, both physically and emotionally, that a commitment to losing hard becomes a first principle of professional life. Every practice, drill or second of competition is informed by that scary investment of self.

Within 48 hours this week, the Wizards and the National Hockey League’s Washington Capitals were knocked out of the playoffs in their 30-team sports in the round of eight, their aspirations snuffed in the last microsecond of their seasons. Seven months ago, the Washington Nationals were upset in the same round of eight in Major League Baseball’s playoffs. All three teams are among the best, close to playing for championships. But they aren’t that close. More hard losers, apply within?

After the Wizards’ loss on Friday night, Bradley Beal and John Wall both used the same word, not in a sentence, but simply standing alone to describe everything: “heartbreaking.”

Right now, Washington fans, who haven’t had a team win a championship in any major professional sport in 23 years, and have only seen one team reach a title round in that time, understand some fraction of what that heartbreak feels like. Imagine that you don’t get to turn off the TV or tear up your ticket stub and turn to other things. Imagine that the game is your profession, a huge slice of your life and identity. How much can you bear to take losing to heart, game after game, year after year?

After Pierce was denied, he said he did not know if he would play basketball again, though he can pick up a $6 million option to play next year. “Truthfully,” said The Truth, “I don’t have too much of these efforts left, if any. These rides throughout the NBA season, throughout the playoffs, are very emotional. They take a lot out of not only your body, but your mind, your spirit.”

In Game 3, with Wall out injured, Pierce hit a 20-foot, fall-away bank shot at the buzzer for the win. National glory. In Game 4, he had an open three-point shot from the wing to force overtime — and missed. In Game 5, with the 24-second clock running out, he hit a three-point shot from the left corner for a one-point lead with 8.3 seconds left; the Wizards lost in the final two seconds. Then, Game 6 — the best and worst emotions of sport separated by a hummingbird heartbeat.

“Days like this, you go home, you’re around your family, you don’t feel like talking to them or doing anything because of what the game does,” Pierce said. “It affects the people around you. It’s tough . . . I won’t have any words for my wife or my mom. Probably the only thing that can get through to me right now is my kids.”

Fans sense this about great athletes, even as they wonder if it is entirely sane, a risk-reward proposition worth accepting or whether it is some sort of devil’s deal that can end up badly in ways you might not anticipate. But they cheer those with this kind of passion. They wear the Pierce T-shirts that say, “I called game.”

On Wednesday, Capitals goalie Braden Holtby lost hard. He lay on his back motionless, the puck still in the net behind him as the New York Rangers, the best team in hockey this regular season, celebrated saving their year by escaping the Capitals in seven games, all decided by one goal, with Game 7 going into overtime to boot.

Holtby lost to Henrik Lundqvist in what some are calling one of the greatest goalie duals in NHL history. Afterward he rebutted all generous questions that were offered to him with a “nice try” clause buried in them.

On Friday night in defeat, Wall’s response was the same. He played the final two games with five broken bones in his hand and wrist; normally, that means your whole paw is immobilized for four to six weeks. Wall went full bore; and he’s always, of necessity, one of the most reckless players in any sport. In Game 6, he had 20 points and 13 assists. Did he think these thrilling, brutal games and the Wizards’ ability to play the 60-win Hawks almost even constituted improvement?

“It’s the same” as in last year’s playoffs, Wall said, quietly, tonelessly. “We lost in Game 6 at home. . . . If we could have had just one more second.” Or one-tenth of that second.

For some fans, the losing may be as hard as for some players. For followers of multiple teams, the supposedly erasable pain of many futile seasons in a row has its own malicious, indelible quality. Seven months ago, in the Nationals’ locker room after their playoff loss, Jayson Werth sat, wrapped in towels, staring into his locker for many minutes as reporters waited for quotes. I waited, too, but left when I realized that he wasn’t going to talk because he couldn’t speak — no words.

Right now, plenty of Washington fans may think, “How much more of this can I take?” They may be thinking about getting off just as it’s time to get on.

Long ago, Washington had teams packed with players who lost hard and demanded it of others. Joe Gibbs’s Redskins. Wes Unseld’s Bullets. Earl Weaver’s Orioles. John Thompson Jr.’s Hoyas. Until the last two or three years, that hasn’t been true of any local team, certainly not the laughing-in-defeat Redskins.

Now it is true of the Wizards, Capitals and Nationals — yes, those recent “losers” or even “chokers” in their most recent playoffs.

At the moment when all three teams needed a lesson in what’s required to go further, rise higher, Pierce arrived in D.C. His style is copyrighted. But what defined him — underneath his trash talk, his arms thrown around Wall and Beal’s necks in a teaching moment — was his willingness to invest his identity, not just his ability in his team.

Whether The Truth returns or not, that truth should remain.

For more by Thomas Boswell, visit washingtonpost.com/boswell.