In 2012 and 2014, this was the series of the playoffs. Now, it feels like the undercard -- to the Warriors' spitting fire, to injuries, to LeBron's melodramatic quest for redemption in Cleveland.

Nope. Thunder-Spurs III is no undercard, especially in the final year of Kevin Durant's contract, with San Antonio quietly discussing what kind of cap gymnastics it would take to get into the Durant derby, per several league sources. The most interesting series of the entire playoffs might be starting on Saturday.

It's almost hard to remember, but two years ago, the Thunder's long-limbed athleticism seemed like Spurs kryptonite. They overwhelmed the 2012 Spurs, fresh off a 20-game streak, with four straight wins that felt cruel and emphatic: We are here, we have figured you geezers out, and we are not leaving. They dominated the Spurs in the regular season after that, and once Serge Ibaka returned from injury for Game 3 of the 2014 conference finals, the Thunder unnerved San Antonio with their speed and bounce.

Those Spurs were anguished after the Thunder evened that series at 2-2, but they found answers. They slid Kawhi Leonard over to Russell Westbrook more, benched Tiago Splitter, and lost themselves in euphoric fits of ball movement. They gave us the ultimate Spurgasm, the best representation of the best version of themselves, and passed-and-cut the Thunder and Heat into weary surrender.

That was the way those Spurs had to play, but they understood it could not be sustained. They reinvented themselves around Kawhi Leonard and LaMarcus Aldridge as a slower, post-heavy meat grinder that minces opponents with perhaps the greatest defense in league history -- a unit with size, wheels, smarts and two All-Defense-level wings in Leonard and Danny Green to make life hard for Oklahoma City's superstars.

Oklahoma City has churned the supporting cast around its central players, but it sometimes seems they haven't evolved -- at least not in the ways that would help them against the very best. Their offense is still predictable, powerful, and low on ball movement. They've tweaked their defense, but the changes appear to have made them worse. It's nearly May, and they still don't know who should play in crunch time alongside Westbrook and Durant -- or if small ball, with Durant at power forward, is even a thing anymore.

Things are about to get real after Oklahoma City's sneering heel turn against a hobbled and overmatched Dallas team. The Thunder could get away with four minutes of lazy, unfocused defense against Dallas. Not anymore. That is the single biggest question hovering over this series: Can the Thunder, just 12th in points allowed per possession this season, put together 48 minutes of coherent defense against a superteam that gives no quarter?

The Thunder started the season by dialing down their manic defense: Big men sagged into the paint instead of blitzing the pick-and-roll, and the coaching staff set clear rules for help assignments. They wanted to keep the ball in front of them, gamble less, maintain basic defensive integrity, and use their athleticism over smaller distances -- to play with calmer frenzy.

So far, they've sacrificed some of the crazy that made them dangerous without gaining the stability they sought. Oklahoma City ranked just 27th in forcing turnovers this season, down from 10th in 2014.

Even with the dearth in turnovers, these Thunder generate more fast-break points than the 2014 version -- suggesting they run like hell off opponent misses and score with vicious efficiency after the few live-ball turnovers they snag. Those opportunities might dwindle against San Antonio; the Spurs are a slow-poke, low-turnover team obsessed with transition defense. They are built to dictate pace against a Thunder team that wants to zip.

In their base defense, the Thunder are prone to mental lapses -- bad bets, botched rotations, and stretches where they just check out mentally.

Westbrook's performance down the stretch of the Mavs' Game 2 win was embarrassing -- an extreme version of the wild, hazy play that can undo possessions.

Tony Parker isn't what he was, but relax for a second, and poof -- he's gone:

Parker struggled against Oklahoma City during the regular-season, and he needs his midrange game on point. The Thunder's defense will present him chances; Westbrook will go under some screens, testing Parker's jumper, and Parker should be able to get into the middle of the floor for teardrops; the Thunder shooed ball handlers away from the middle on only 38 percent of side pick-and-rolls.

Parker-Aldridge was San Antonio's most-used pick-and-roll combination, per SportVU data from STATS LLC, and it will be interesting to watch Oklahoma City toggle between antidotes. Duck under, and you gift Parker jumpers. Have Westbrook scamper over the screen, and Aldridge feasts on midrange pops. The Thunder have tried to snuff that by having Ibaka, their primary Aldridge matchup, stay attached to Aldridge while hedging out just a hair to bump Parker. Screw that up, and Parker can turn the corner, or Aldridge might slip clean to the rim:

Facing Dirk Nowitzki in the first round was a nice warm-up. Nowitzki rolled hard as Ibaka lunged out, but the Thunder mostly contained him because their centers were always nearby to patrol the rim -- just as Enes Kanter is in the above clip.

Nowitzki would then settle into post-ups, and he hurt Ibaka on the block. Aldridge has, too. Aldridge can shoot over Ibaka, and has been determined in bullying him closer to the rim for righty hooks.

Thunder coach Billy Donovan should at least try Steven Adams on Aldridge, as he did now and then with Nowitzki. Adams is fast enough to track Aldridge around the perimeter, and burly centers have gotten under Aldridge's skin before. That would leave Ibaka on Duncan, and Thunder fans remember how Duncan tore apart that matchup down the stretch of the Spurs' Game 6 clincher in 2014. But that's life at this level. The best teams have counters for everything. You just have to find matchups that tilt the math a teensy bit your way, and shift between tactics enough so that no strategy gets stale. Using Ibaka on Duncan a bit would also leave the Thunder big closer to the rim, where he scares all comers.

Trying Adams on Aldridge would make the Thunder a little less switchable, and they like to switch. If Ibaka is on Aldridge, he and Durant will swap assignments anytime Aldridge and Leonard screen for each other; they are confident Durant can deal with Aldridge on the block, and that Ibaka can track almost any perimeter player.

A few coaches and scouts suggested the Thunder should amp up the switching, even if it leaves Westbrook guarding a monster like Aldridge or Tim Duncan. Westbrook could front those guys, and even this version of the Spurs does not like bogging down in mismatch basketball. They posted up more than anyone in the league, but they also ranked fourth in passes per game. Baiting them out of their core identity could be a net win.

Switching brings another bonus: Get a stop, and the assignments are scrambled -- opening a window for those rampaging Thunder transition attacks, where it almost looks like they are playing their own very fun version of a different sport.

But these Spurs are better-equipped to attack mismatches; Leonard perks up whenever he finds someone other than Durant on him, even if it's Andre Roberson, a smart and long defender who can't quite handle Leonard on the block.

Kanter has worked himself into a playably bad defender, and he was unstoppable around the rim against Dallas, gobbling rebounds and drop-off passes from Westbrook. The Spurs prefer to play two bigs, and Kanter should have a place to hide on defense -- usually David West. But Kanter comes off the bench, and that means his minutes will overlap with those pass-happy Patty Mills-Boris Diaw-Manu Ginobili lineups.

Their delicious Spursy motion might make them a more difficult matchup for Kanter than the San Antonio starters. West has slowed down, but he's a capable enough pick-and-roll player for the Spurs to poke at Kanter over and over until the Thunder bleed.

Kanter is a core part of Oklahoma City's identity -- mustachioed evidence of Sam Presti's belief that you win in the NBA with size at all positions. He turned the Thunder into an all-time offensive rebounding team during an era when no one seems to care much about offensive rebounds; Oklahoma City rebounded 31.1 percent of its own misses, the highest mark in the league by a mile. The gap between the Thunder and the No. 2 team -- Detroit, at 27 percent -- is the largest gap between the No. 1 and No. 2 offensive rebounding teams in league history, per Basketball-Reference.com.

It makes such basic sense: Westbrook and Durant draw a ton of attention when they shoot, and Kanter slips into the vacuum to mooch misses. He will pulverize anyone the Spurs throw at him, including Duncan:

Ever since Donovan started staggering minutes for Westbrook and Durant, one of them is always on the court to serve as the enabler for Kanter's rebound addiction. Bad news: The Spurs finished as one of the half-dozen best defensive rebounding teams ever. San Antonio has the goods to win this game-within-a-game, or play it to a draw, and make the Thunder earn it on their first shot attempt.

The Spurs will know the likely source of those shots before the Thunder even cross half court. Everyone does. Scouts like to say the Thunder play their crunch-time offense, with a few scripted set plays, from jump street. The Spurs have seen all these movies a thousand times: the Westbrook-Adams spread pick-and-roll surrounded by three shooters; all the pin-downs and cross-screens for Durant; the Westbrook-Ibaka pick-and-pop; and the dreaded Westbrook-Durant two-man game.

No team is better prepared than the Spurs, with Green and Leonard, to switch that last play. Parker might defend Westbrook for the first possession of the series, but that will end quickly. The Spurs know Parker can't handle Westbrook, especially now that Westbrook is a mean-spirited post player:

Westbrook has created an astonishing number of easy baskets for Adams by overpowering some poor sap on the block, waiting for Adams's defender to help, and threading the easiest available pass to Adams near the rim. The Spurs are going to vaporize those baskets.

Both Green and Leonard will see time on Westbrook, and depending on the flow of the series, Leonard might end up the better choice. He's the best choice for Durant, too, but even the Sharktopus can guard only one guy.

Westbrook has too much speed and power for Green -- for anyone, really. When Green slithers under picks, Westbrook zooms downhill, beats Green to the spot, and flies to the rim:

He'll beat Leonard now and then the same way, but Leonard slides a tick faster than Green, and his arms are much longer; Leonard has a better chance at meeting Westbrook on the other side, or bothering him from behind. The Spurs might opt to chase Westbrook over picks, banking on Duncan and Aldridge to corral him -- and force floaters and midrange shots that are the least of all the evil Westbrook might inflict. He is so explosive, he'll get to the rim a bunch anyway.

The Spurs will mix and match assignments and strategies. There is no real answer for Westbrook and Durant. There is only pain management. They give The Thunder a fighting chance just by striding onto the floor together, and they can win entire games on their own. They will each need to play monster minutes -- like 42 per game, maybe more -- for Oklahoma City to pull this off.

The best answer, of course, is to send help off Oklahoma City's other players, crowd Durant and Westbrook with extra bodies, and present them a choice: take brutal shots from outside the paint, or pass to a lesser teammate.

That will be easy as long as Roberson is on the floor. The Thunder might finally be meeting the defense that renders Roberson unplayable and forces Donovan to start Dion Waiters -- or someone else. The Spurs will treat Roberson on the perimeter as if he isn't even there, and his cute baseline cuts won't work as often as they do against other teams.

The Spurs are going to tilt their entire defense toward Durant and Westbrook:

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San Antonio's big men will feel brave venturing away from their assignments, knowing whoever is guarding Roberson has their back -- as Green does here, already claiming inside position on Adams so that Duncan can trap Westbrook:

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Waiters shot 36 percent from deep, and he can beat scrambling defenders off the dribble when Durant and Westbrook swing the ball to him. He's an underrated passer, and he pierced the Mavs with his secondary playmaking.

That doesn't mean San Antonio will afford Waiters -- or Kyle Singler, or Cameron Payne, or Randy Foye, or Rumble the Bison -- much more respect if doing so compromises their defense on Westbrook and Durant. Anthony Morrow is another story, but the Spurs would eat him alive on the other end.

The Thunder will see bodies, everywhere. When Ibaka catches a pass from Westbrook on the pick-and-pop, some Spur will flash into his line of sight:

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Hell, they'll even crash off Westbrook at the top of the arc when Durant speeds off a pin-down:

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Playing two traditional big men isn't a death sentence; the Spurs do it, too. It does make it easier for Oklahoma City's opponents to strangle the floor. Ibaka and Kanter are both good shooters, and Kanter has toyed with a corner 3. But they are most comfortable from 20 feet and in.

The Thunder have a killer offense. Opponents are scared of them. Their stars make crazy shots and arrive at the rim before you even know what the hell just happened. They can create an open midrange jumper whenever they want. But the Spurs are so good -- so huge and smart -- that they can keep up with almost anything within the 3-point arc:

The Thunder will score in this series. The question is whether they will score enough to beat San Antonio -- the third-best offense in the league, by the way -- four times. They have avenues to get there. They should feature more spread pick-and-roll with Westbrook, using Durant to space the floor, ready to catch and go once Westbrook has compromised the defense:

"That's what we want," Nick Collison told me in February. "We want Kevin catching the ball [from Westbrook], and attacking closeouts."

Durant needs touches, and the Thunder might be able to get some traction slotting him into pick-and-rolls with Duncan's man; Duncan wants to hang near the paint, and if Durant gets a solid screen, he might be able to rise for clean 3s:

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If the Spurs hide Parker on Waiters or Roberson, maybe the Thunder should get crazy and use them as screeners for their stars -- a way to involve Parker, and maybe force him to switch into ugly mismatches.

The Thunder have to try everything. Predictable one-on-one ball can get you only so far against a historically dominant (regular-season) team.

The most obvious way to juice the offense and stretch San Antonio to its breaking point would be something the Thunder don't do much these days: play small, with Durant at power forward. Maybe it wouldn't make a difference, anyway. The spare Thunder wings aren't much more skilled with the ball than Ibaka, and can't rebound or block shots like Kanter and Adams. Diaw and Aldridge could guard any of them.

If the Thunder go small, the Spurs could just counter with something like Parker-Green-Leonard-Diaw-Aldridge, and have Diaw guard the least dangerous wing -- and then beat the living crap out of that sucker in the post on the other end.

And that's the thing: The Spurs have built-in ways too chip away at every Oklahoma City advantage -- the Thunder's size, offensive rebounding, transition game, and even their star power. Donovan is facing one of the all-time great coaches in Gregg Popovich, and Donovan's work so far doesn't suggest he'll make the best choices -- whatever those are -- in a timely fashion.

San Antonio has been better all season, they've lost only a single game at home (to Golden State, no less), and they are the favorites here.

Prediction: Spurs in 6