As Houston coaches gathered in a Las Vegas high school gym in July to watch what they assumed would be a casual pickup run between summer leaguers and the real Rockets, a scream pierced the air.

"FLARE SCREEN!" someone yelled with Game 7-level urgency. "FLARE SCREEN!"

It was Chris Paul. A few minutes later, Paul stopped the scrimmage, jogged over to the coaches, and asked how the Rockets defended an action the summer leaguers had just run.

"It was like Christmas," says Jeff Bzdelik, Houston's associate head coach and defensive coordinator. "Chris is a militant, and I mean that in a good way."

James Harden, the incumbent star who sometimes approaches defense with the slumped indifference of a teenager asked to take out the garbage, was familiar with Paul's militancy by then. He accepted it when he urged Daryl Morey, Houston's GM, to nab Paul after years of unrequited pursuit. He had witnessed it face to face a few days after the trade, when Paul reached Harden at night and said he wanted to meet -- right then -- at a restaurant in Los Angeles.

Paul had been waiting to ask Harden one question: "What is your ultimate goal in basketball?" Harden said he wanted a title. "He said he was excited about not having to do it all -- about getting the ball out of his hands a bit," Paul remembers. Editor's Picks Lowe's 10 things: Let's get the All-Star draft right

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That's easy to say in July. It's also easy to say when you're 25-5 with a historic offense and rugged, switchable defense, the first true non-LeBron threat to Golden State's hegemony, but the two stars have felt the benefits of the arrangement sooner and more profoundly than they expected.

After Monday's win over Utah, Mike D'Antoni, Houston's coach, apologized to Paul for playing him 34 minutes -- more than their target. Paul waved him away. "Thirty-four here is like 25 in L.A.," Paul told D'Antoni. "Not having to dribble the ball up every time -- this is a breeze."

Paul knows he is caricatured as a walk-it-up general who likes to bark orders and signal plays. He insists that is wrong. "It's neither here nor there at this point, but I was asking for a while to get the ball out of my hands," Paul says.

When told of skepticism about that, Paul sits up in his chair. "How many times have we run floppy this season?" he asks, referring to a curl play for J.J. Redick he might have called a thousand times. A visitor shrugs. "Come on, guess." Ten? "Ze-ro," Paul exclaims. "Zero. We don't even have floppy in the playbook." D'Antoni hasn't installed a single Paul-specific action.

Meanwhile, Harden wilted in last season's conference semifinals. Houston officials insist they saw exhaustion sapping him as early as Game 1 against the Spurs -- in part the toll of Harden's relentless pursuit of the MVP award. "He should want to win MVP," D'Antoni says, "but we have to be careful." Irv Roland, a Rockets player development coach who has been among Harden's closest confidantes for almost a decade, says the two have still never discussed Harden's season-ending, 2-of-11 dud.

If they were willing, the stars could help each other stay fresh deep into the playoffs. Morey first had that vision in the summer of 2013. Paul's representatives have told Morey the Rockets might have nabbed Paul then had the Clippers not finalized their deal for Doc Rivers before the start of free agency, Morey says. The Rockets signed Dwight Howard instead.

As Jackie MacMullan reported in the fall, Paul kept the custom bobbleheads Houston prepared for that 2013 courtship. The Rockets traded for him this time around, but after the deal, Paul insisted on watching the videos (displayed below) Houston put together for the July 1st free agency pitch meeting that never happened -- "even the iPad stuff everyone makes fun of us for," Morey says.

Morey and D'Antoni expected some early awkwardness. They thought Paul would need time to absorb the freedom and pace of D'Antoni's offense. Even role players do. In one of Raja Bell's first games under D'Antoni in Phoenix, he bricked a catch-and-shoot 3 early in the shot clock and sheepishly asked his coach: "Was that a bad shot?" the two recall. D'Antoni answered with a question: "Did you think you were gonna make it, Raja?" Bell did. "Make it next time, and it'll be a good shot," D'Antoni concluded.

"I thought we'd have some bumps," D'Antoni said. "But from Day 1, they just figured it out."

The results have been scary. Houston looks like a legitimate challenger to the Warriors, and they have only begun experimenting with some lineups variations -- small-ball looks with P.J. Tucker at center, and hyper-speed groups featuring Harden, Paul and Eric Gordon. They are daring to imagine how those three-guard lineups would match up against the Warriors: Who would play power forward? Would one of the three Houston guards defend Draymond Green, so that nominal power forward could chase Durant?

"They set the bar," D'Antoni says. "But we think, modestly, that we match up well against them."

They are underdogs, maybe big ones, but Morey has long promised that he will go for it if he thinks Houston has even a 5 percent chance of winning a ring. He will hunt likely LeBron this summer, per league sources, and hopes to sign Paul to another long-term deal. With Clint Capela and Trevor Ariza headed toward free agency, just bringing this group back could vault Houston well into the luxury tax. Tilman Fertitta, the team's new owner, has said he would pay the tax to preserve a contender.

"We think we have a five-year window with Chris and James," D'Antoni says. A max deal for Paul would be a risk given his age and injury nicks, but Morey will gamble to wring everything from Harden's prime. "It will be up to Chris," Morey says, "but we feel good about it."

Of course, the Spurs exist, and they blocked Houston's path to the conference finals last season. That series has driven much of what Houston has done since, and reinforced their instinct that Paul would add a needed diversity on offense. San Antonio found a smart way to defang Houston's pick-and-roll barrage, and it has spread around a copycat league.

San Antonio's Harden Rules: The big man guarding Capela, Harden's main screener, plants himself deep in the paint -- opening a runway to the rim, and conceding midrange jumpers Houston refuses. That defender has one job: Wait for Harden to arrive, and raise your arms to the sky.

Next: Put a wing on Ryan Anderson, and switch the lethal Harden-Anderson pick-and-pop. If you have a second big man, slot him onto the weakest remaining wing player -- Ariza last season -- and dare Harden to use that guy as his screener.

The idea was obvious: Turn Harden into a driver, stay home on 3-point shooters, and disrupt Harden at the rim without hacking the bejesus out of him.

It worked. "What they did to us," D'Antoni admits, "is probably the best you could do." (That series explains a lot of Houston's offseason fascination with Carmelo Anthony -- another isolation scorer to get buckets when things bog down.)

Houston views Paul as the antidote. Coax Houston into midrangers, and Harden can swing the ball to one of the greatest midrange shooters ever. It has already worked in crunch time:

"I'm not worried about combating that," D'Antoni says of the Spurs' scheme. "James will have more pop this season, and now we have Chris."

Smart defenses will adjust, and devise separate approaches for Paul and Harden. Some opponents prefer a more traditional scheme in which help defenders swarm the paint -- but only off of Ariza, Tucker, or Luc Richard Mbah a Moute spotting up for longer, non-corner 3s.

That gambit echoes how teams defend the Warriors: make Green and Andre Iguodala beat you.

It sounds simple on paper. Last season's wheezing Rockets almost made it simple -- as "simple" as containing a Hall of Fame player can be -- when they slowed to a crawl and ran everything through Harden. Even now, with Paul, there will be moments when opponents force Houston's lesser lights to make plays:

Mbah a Moute and Tucker barely dabbled in longer 3s before this season, but they are 36-of-82 combined -- a tidy 43 percent -- on non-corner triples.

And of course, Houston can rush into things before the opposing defense sets up -- the luxury of having two expert ball-handlers ready for outlet passes. Houston leads the league in points per possession after defensive rebounds, per Inpredictable.

"It feels like Phoenix sometimes," D'Antoni says, "but with a two-headed Steve Nash."

Opponents are busting out so many defenses that the Rockets feel as if they are living an 82-game postseason chess match. In a film session the morning after their Monday win over Utah, D'Antoni flipped between all the different tactics the Jazz used within one game: drop-backs, switches, hard traps. Houston solved them all.

As the video rolled, Tucker turned to Roland and whispered: "How would you even scout us?"

"I don't care what defenses do, they're not guarding us," D'Antoni says. "Maybe that's an exaggeration, but I want our guys to feel that way. We might mess up, or we might not shoot well. But it won't be because of the defense. It's about us."

Double Harden, and Capela -- putting up preposterous numbers -- has grown comfortable making plays off the bounce, and spraying the ball to open shooters:

(Always keep an eye out for murderous Tucker flare screens like the one he aims at Joe Ingles there.)

If a defense is frustrating Houston's base pick-and-rolls, D'Antoni opens his book of intricate set pieces. One of his biggest challenges has been remembering that Harden and Paul like the ball on opposite wings. "I draw something up, and it's like, 'Oh, s--, I have to flip it around,'" he laughs.

When defenses start switching every pick, Houston can just stop setting them. They like to shift Anderson to center, spread everyone around the arc, and let Harden drive one-on-one into an empty paint. It is caveman basketball, but no one can stay in front of Harden. Opponents face a brutal choice: help and give up 3s, or watch Harden run a personal layup line.

Houston can also stick with its pick-and-roll game, knowing Harden and Paul rank among the very best at roasting big men on switches.

Add it all up, and the Rockets have scored 1.15 points possession on isolation plays, per Synergy Sports -- best in the league by a mile, and on pace to be the highest such figure in 14 seasons of Synergy archives by a laughable margin. (No team has ever cracked the 1.0 barrier.)

Isolation ball goes against D'Antoni's core beliefs, but he cares more about efficiency than style. "I've never been like, 'You have to play this one way,'" he says. "If something works, it works."

Anderson's gravity opens up extra space for those one-on-one forays; he and Capela will serve as bellwethers for Houston's defense in the postseason. Anderson has always been a liability, and the Spurs torched him in last year's second round. These Rockets are versatile enough that they can slash Anderson's minutes almost to zero. But on some nights, they will need his shooting to loosen defenses.

Anderson shed a dozen pounds thanks to a summertime anti-inflammatory diet in hopes of moving better on switches. It paid off.

"I've never been known as a defender," Anderson chuckles. "I'd like to be known now as maybe, somewhat of a defender. Just a little bit?"

Capela feels essential to any ambitions of overthrowing the Warriors. He is by far Houston's best rim protector, and the Warriors, for all their flame-throwing, gear a lot of their offense toward rim runs. Without Capela, the series becomes a pure shootout, and I'm not sure even these Rockets can keep up with a healthy Golden State team in a shootout.

"I've told Clint," D'Antoni says, "that he's the key."

Capela has taken well to Houston's switch-heavy scheme. "I can do everything on defense," Capela says, "and I can guard anybody." But switching against Golden State is different than switching against everyone else. The Warriors run big men through a gauntlet of screens and cuts until they finally break.

Houston is hopeful Capela will be up for any challenge. Mbah a Moute and Tucker can guard at least four positions apiece, and Nene Hilario has long been a switching ace.

Switching on defense powers Houston's offense. It jumbles the matchups so that after a stop, opponents have to either accept mismatches or crisscross the court in search of their normal assignments -- chaos that leaves shooters open in its wake. Houston's switching is predatory as much as it is reactive.

Before this season, Houston didn't rebound well enough out of switches to capitalize. The Rockets have made a remarkable turnaround; they are neck-and-neck with Charlotte for the top spot in defensive rebounding rate after finishing 21st last season and dead stinking last in 2015-16.

When the coaches broke last May, they vowed to make it a daily talking point. In every practice, they run drills that simulate rebounding in specific situations -- including after switches, when Houston must gang rebound to help little guys stuck boxing out behemoths. "We realized that we can't get frustrated about something if we don't emphasize it," Bzdelik says.

The coaches often distribute charts showing players how many more points per possession Houston scores after a stop. The message: Do the grunt work, and you will eventually reap some glory.

Houston ranks eighth in points allowed per possession. We'll see if it holds. They yield a ton of shots at the rim and a decent number of 3s. Their transition defense, the bane of Bzdelik's life for two years now, is rickety. "We can't be one-way runners," he says.

But the personnel outside of Harden and Anderson is solid. They mostly play hard, moving together on a string, and they're well-prepared for each opponent. They have shown an extra gear for big moments.

Paul will not let them rest, anyway. When opponents call timeout to interrupt a Houston scoring spasm, Paul is fond of gathering his teammates and exhorting: "The next stop is the most important stop!"

"It reminds me of Miami," says Bzdelik, who coached there under Pat Riley in the late 1990s. "We had Zo [Alonzo Mourning], Dan Majerle, all these veterans who would say: 'Let's keep kicking their butts and have ice on our knees in the fourth quarter.'"

D'Antoni wants to save their legs, too. He is battling both his instincts to overplay a short rotation and Harden's MVP obsession -- Harden's pure, ironman love of playing. D'Antoni has already scrapped morning shootarounds so players can sleep more, and believe it or not, Harden was the last holdout. He craved a deadline to get him going in the morning.

Paul is finding the balance between keeping things fun and maintaining a focus on the big picture. He is having everyone on the team fitted for personal bowling balls, and the Rockets laugh together a lot. But they know what is at stake. They will need some luck to beat the Warriors -- if they even get there -- and Paul promises they will be ready if the basketball gods provide it.

"We have a chance," Paul says, "to become special."