Pay attention. This doesn’t happen every decade, even every generation. Wherever you sit during Washington Nationals games, on your favorite couch in front of the TV or in the bleachers on South Capitol Street, don’t change seats. Eat the same pregame meal. Lucky charms — don’t lose ’em. How far can this thing go?

Nothing in baseball is more pure summer fun, mixed with just enough tension to be deliciously fretful, than a long winning streak. In the Washington Nationals’ case, that skein has now reached 10 victories with a 1-0 walk-off win over Arizona on Thursday. How rare is 10 wins in a row? The Cincinnati Reds have been one of the game’s great franchises since 1882. Their longest streak: 12 .

A win Friday night at Nationals Park would be the longest winning streak by any D.C. big league team since 1933, when the Senators won 13 in a row — yes, that’s the last year a D.C. team won the pennant.

When you spike that 10-0 streak improbability with the even rarer punch of walk-off wins on Saturday, Sunday, Monday, Wednesday and another in the ninth on Thursday — five instant victory celebration in six games — you have a unique cocktail, potent enough to make any fan dizzy.

How rare is five walk-off wins in six games? It has happened only seven times in baseball history. The last time, in 1986, the Astros actually won five straight that way. So combine the intoxication of a big winning streak — which has knocked the Atlanta Braves seven games behind in the NL East — with the ludicrously wonderful ways in which the Nats have won and you have late-game insanity squared.

Since the All-Star Break, Rafael Soriano has three blown saves and a 7.71 ERA in 11 appearances. The Post Sports Live crew debates whether the Nationals should be concerned by the closer's performances. (Post Sports Live/The Washington Post)

And other teams know it. In the first seven innings of their latest adventure, the Nats put 14 men on base and wasted them all. But Gio Gonzalez rediscovered his misplaced curveball, had his sharpest game in weeks and pitched seven shutout innings. The Nats had just been setting the stage.

When Denard Span singled in the ninth, Diamondback first baseman Mark Trumbo said, “Just how you guys like it.” Little did Trumbo know that the foreshadows were gathering around him. Span stole second. Anthony Rendon hit a grounder to third base and Trumbo missed the one-hop errant throw to first of Jordan Pacheco. That’s when the Nats went to the well one more time — this time, it was the camera well. That’s where the wild throw trickled as Span stood between second and third.

Would Span be awarded home or would he have to stop at third? Had he moved toward third base enough for the umpire to grant him the extra base? Ump James Hoye waved him in — a pure Diamondback gift. For perhaps three seconds, every Nat froze. Then it hit them at once. After all their comebacks, after overcoming three of their own blown saves this week to win anyway, they were actually getting a victory for free.

Long winning streaks are part of the fabric and lore of baseball. They just aren’t part of the fabric and lore of D.C. As a kid, I became a Senators fan in third grade. I was a sophomore in high school, more than seven seasons and 1,100 games later, before I saw my first winning streak of more than five games.

We heard that other towns had streaks that stretched for weeks, not days. The 1916 New York Giants won 26 in a row, though with a tie game stuck there. The Cubs once won 21 in a row. But from 1956 through the team’s exodus in ’71, D.C. had only six winnings streaks of more than five games in 15 years. Newspapers hailed anything longer than back-to-back wins as a “streak.” Better use that “Nats Win Streak Hits Three” headline while you still can.

Now times have not only changed but inverted. Go on, get excited. The Nats’ series with San Francisco this weekend is history knocking.

If the Nats win their next two games — difficult, but hardly irrational for the team with the best record and margin of victory (102 runs) in the NL — they’d have 12 in a row. That would put them ahead of the all-time best streaks of the Marlins (nine), Expos/Nats (10), Blue Jays (11), Mets (11), Angels (11) and Rockies (11). And they’d be tied with the best streak of the Astros, Rays and, yes, Reds .

Just as in 2012, the more the Nats win, the more fun and foolishness they generate. In a May 2 interview, MASN’s F.P. Santangelo showed a tape of Matt Williams in 1991 doing an excellent comic impression of Babe Ruth waddling out a home run — rounding the bases with tiny quick Bambino steps, doffing his cap to the adoring in the crowd, giving the ol’ razzoo to those who were booing. If the Nats won 10 in a row, would the Nationals’ manager do his old routine again — as incentive to the team? Oh, sure, no prob.

That was then. Now it is time to pay up. “A promise is a promise,” said Williams. “I’ll do it, probably in the privacy of some stadium somewhere. Now [in a pennant race] it’s not appropriate.”

Later, by his office, still chuckling, Williams, “Sometime, somewhere — like Field 4 in Viera.”

Williams and his staff, creatures of baseball superstition, have other streak-induced issues that are far more pressing. Sometimes Williams and several coaches, including Randy Knorr, Tony Tarasco, Bob Henley and Mark Weidemaier, take a three-and-a-half mile mid-day jog from Nats Park around the U.S. Capitol building and back. It’s a trek they don’t do every day. But they did it the day the streak started, then the next. “Let’s just say my staff is exhausted,” said Williams. “We’ve run it every day.”

Part of Williams resists anything as potentially emotional as a long winning streak. If he doesn’t say “never get too high or too low” at least 20 times a day, he gets a rash. Every day he practically apologizes for the previous miracle win. One smile is the usual allotment, though his mouth has to be suppressed in mid-grin sometimes.

“I love to see them do well,” Williams said of his players. “But I refuse to get too high or too low.” Only 19 more to go.

“It doesn’t work for me. It doesn’t work for our team.”

The hijinx happen when outsiders can’t see. The post-victory smoke machine and loud music, conceived months ago by Kevin Frandsen and Jayson Werth, have both dissipated by the time the game is analyzed. “The game’s a roller coaster,” said Rendon. “It’ll come down.”

But now, all the Nats and their followers are strapped in their seat at the very top of the arc, hearts in mouth for what will happen next. What the Nats have done in the last 10 days — the combination of the wins but also the ways it was done — probably won’t happen again for Washington baseball in most of our lifetimes. And, unlike the last week of a playoff race or the post-season, there’s no grievous penalty when the inevitable defeat comes. Baseball even has a stock phrase: We just start another one.

Switch around your mind, your TV set or your weekend plans. Or at least consider it. On a Thursday afternoon, 32,341 came to see No. 10. Who would you want to try for No. 11? Yes, Doug Fister, with the 1.89 ERA in his past 17 starts (14-3 team record) against that notorious Nat-killer Tim Hudson. Tough job.

Kids of all ages, this won’t come again — not exactly this concoction at the very moment the Nats swell to 20 games over .500 and look like they just might be as good as anybody. So, same seat, same good luck charms, same socks. Okay, by Day 11, maybe not the socks.