ON A PREVIOUS triumphant day of baseball in Washington, the stadium erupted in mayhem when the home team entered the history books with a walk-off win in the deciding game of the World Series. As The Post reported, the crowd of 35,000, “delirious with joy, broke into a bedlam on the field that had never been duplicated in point of volume and intense excitement in the annals of sporting history.” The Washington mob was so unruly that Walter “Big Train” Johnson, the local team’s ace, fled the ballpark in a fast motorcar, trailed by a “sea of humanity in an endless snake-dance,” and the Secret Service was all but helpless to protect President Calvin Coolidge and his wife, who quaked in the presidential box.

The current season, despite its liberal dose of magical moments, has yet to scale the heights of October 1924, the one and only time a major-league team in the nation’s capital went all the way. But this year’s Nationals may do it yet.

On the first Monday in October, when the opening of the Supreme Court’s new term usually stirs more excitement than does baseball in Washington, the Nats clinched the championship of the National League’s Eastern Division. Crowd control having evolved in the past 88 years, fans were kept off the field this time. But the players, having donned gray T-shirts commemorating their accomplishment, partied with champagne as their followers in the stands roared. The pennant race was on, and it was here.

Sure, there were doubts and anxieties and questions. How would the Nats’ roster — 10th-youngest among the majors’ 30 teams — hold up to playoff pressure? Would the team’s starting pitchers meet the test, with its insanely talented young fireballer, Stephen Strasburg, benched until next spring? Would the offense, by turns superlative and supine, rise to the occasion?

The answers will come this weekend as postseason play begins. In the meantime, we know some things for sure: The 2012 Nats have won almost 100 games, a staggering performance predicted by almost no one. They are poised, by dint of youth, talent and quality management, for many years of playoff contention. And baseball’s autumnal delirium, absent from this town for so many decades, is back at last.