The notion struck midway through another second quarter in which the Atlanta Hawks were extracting, without Novocain and with great force, the “d” from Indiana. “The Pacers can’t guard the Hawks,” declared a correspondent watching from on high, “and the Hawks can guard the Pacers. How’d that happen?”

These are the Hawks and this is the postseason, so who knows? But know this: The Hawks can win this series and if they do, it won’t be much of an upset now. Indiana, the East’s No. 3 seed, just spent two games in Philips Arena making a case for itself as the most overrated team in the history of basketball, and the unloved Hawks … well, they’ve been lovely.

Yes, this best-of-seven is tied at 2, and yes, the Hawks will have to take a game in Indianapolis, where they lost twice last week by an aggregate 32 points, in order to advance, but the dynamics of this matchup have been inverted. The Pacers, with much to lose, seem capable of losing it all. The Hawks, whose modest mission this season was not to stink before the real rebuilding begins this summer, look like a team constructed by a master craftsman.

Fun with numbers: The Pacers were second in the NBA over the regular season in fewest points yielded (90.7) and best in field-goal defense (42 percent). Through four games of this series, the Hawks were averaging 95 points — remember, scoring usually dwindles in postseason — and had made 46.6 percent of their shots.

In the first half of Monday’s Game 4, the Hawks scored 55 points — they would win 102-91 — and made 55 percent of their shots. They led by 17 at the break two nights after leading by 24. They actually scored one more point in this first half than they had Saturday. So much for Frank Vogel’s defensive “adjustments.”

The Hawks outscored Indiana 35-19 in the quarter, converting on 15 of 22 possessions. Carried back to the shank of the first period, when the Hawks overrode a modest Pacer lead, they scored on 18 of 25 trips. Teams don’t do that at playoff time. But the Hawks did.

Said Josh Smith: “When the ball moves, we’re hard to guard.”

The Pacers, meanwhile, did next to nothing. They’d made but 27.2 percent of their shots in Game 3 — a low for any NBA playoff team since April 30, 2005 — and they warmed only slightly, to 36.6 percent, in Monday’s first half. How exactly did these guys get to be the No. 3 seed, anyway?

We finally began to see in the second half. Al Horford sat with his fourth foul and Smith started missing shots (six in the quarter) and bricking free throws hand over fist (also six misses in the quarter) and the Pacers outscored the Hawks 15-1 to draw within four. But Indiana went the final four minutes of the period without a basket — this team is pedestrian on offense — and the Hawks held the lead.

Still, the Pacers had given themselves a chance in the fourth quarter, something no visiting team had yet had in this strange-and-getting-stranger series. They pulled within 70-65, whereupon Smith shook loose for a dunk and Paul George, whose star is dimming before our eyes, fumbled the ball and Anthony Tolliver hit a 3-pointer from the corner. And now you’re saying: Anthony Tolliver?

Yes, Anthony Tolliver. He averaged 4.1 points in the regular season, but he had nine in Game 4 and has become essential. So has Johan Petro, another deep-bencher. Petro was deputized as a starter for Game 3 and deemed so indispensable for Game 4 that the Hawks dispatched managing partner Bruce Levenson’s private jet to fetch him Monday afternoon from a Florida delivery room, where he’d witnessed the birth of his first son. (Mother and child are doing fine, thanks.)

Some nervous moments remained. The Pacers cut the deficit to five inside 3 1/2 minutes and George hoisted a trey, but it clanged. (He missed 10 of 16 shots.) Then Smith, whom this writer believes should never take a 3-pointer, lofted a 3-pointer over the raised arms of David West, who slumped when the shot dropped.

Then Smith — he would finish with 29 points, 11 rebounds and four assists — rose to grab the rebound of a wild Horford miss and found Kyle Korver on the right wing. Kyle Korver did as Kyle Korver does and the series was square.

So what happens now? The Pacers are very good at home, but they’ve been handed real reason to doubt. The looks on their faces during that second quarter spoke of anger and frustration but mostly bewilderment. This series was theirs to win. They’re in peril of losing it to a team that was built to be torn down.