The Spurs raced out to a big first-half lead before giving it all away and falling behind in the third quarter, only to jump out ahead again thanks to huge performances from their three stars (Tim Duncan, Manu Ginobili and Tony Parker), Danny Green and Boris Diaw—plus an unexpected lift from little-used backup big man Aron Baynes.
How did they do it? Let's go to the tape.
As was noted multiple times in the lead-up to the series, San Antonio blitzed the Thunder to the tune of 120.8 points per 100 possessions in the 44 minutes that Serge Ibaka rested across their four-game regular-season series, according to NBA.com. Conversely, the Thunder held the Spurs to a paltry 93.0 offensive efficiency in 148 minutes with Ibaka on the floor in those games.
Much of this was due to his elite rim-protection capabilities. Ibaka was a top-three rim protector in the league this season, according to SportVU player tracking data provided by the NBA in conjunction with Stats LLC. San Antonio shot only 47-of-98 (48.0 percent) in the restricted area against the Thunder with Ibaka on the floor, compared to 13-of-21 (61.9 percent) when he sat.
"Obviously it's a different game without Ibaka. He's one of the best defenders in the NBA," said Tony Parker after the game, according to SB Nation's Evans Clinchy. Ibaka's absence was probably the most noticeable thing about Game 1, as the Spurs shot an utterly preposterous 25-of-29 (86.2 percent) in the restricted area on their way to outscoring the Thunder 66-32 in the paint.
Tim Duncan in particular had no trouble finishing over, around and through Kendrick Perkins, Nick Collison and Steven Adams near the basket. This was especially true in the first half, when he made nine of his 12 shots, including all eight from inside the lane.
Collison is a sound defender who is almost always in the right position, but he doesn't have the length or the explosion of Ibaka. Duncan and the rest of the Spurs were unafraid to challenge him near the basket. Perkins is even more ground-bound than Collison, and Adams, while the most athletic of the three, is also the least fundamentally consistent. He is often out of position and even more prone to fouling.
When Oklahoma City went small, San Antonio would just put the lone big man directly into the pick-and-roll action, forcing Durant, Caron Butler and even poor Jeremy Lamb to work as the back-line help defender—a role none of them is quite used to playing.
Speaking of small lineups...
The size battle
As noted by Grantland's Zach Lowe in his series preview, "Downsizing is a way to generate spacing for which the Thunder starters will be starved without Ibaka’s midrange jumper." That actually was the case in Game 1; Oklahoma City played "small" with Kevin Durant at power forward for 25 minutes (according to an analysis of NBA.com's media-only stats-site lineup data), during which it shot 21-of-38 (55.3 percent) from the field and scored 58 points.
The problem was the Thunder also allowed San Antonio to shoot 28-of-45 (62.2 percent) and score 68 points in those 25 minutes of play.
Meanwhile, the Spurs played "small" with only one traditional big man on the floor for 20 minutes of game time, during which they shot 24-of-36 (66.7 percent) from the field and outscored the Thunder by 22 points. Oklahoma City shot 14-of-34 (41.2 percent) in those minutes.
Too often, the Thunder's back-line help defense was either invisible or far too late, as in these Ginobili pick-and-rolls with Baynes late in the third quarter.
Knowing Baynes is not much of a threat to score as the roll man in these situations, Adams tries to trap Ginobili as he comes around the screen, but the Argentine is too quick and crafty to be confined by a good -but-not-great trap. He slithers around Adams and sees this:
Durant should easily be able to rotate across the paint and contest Ginobili's drive to the rim, but that's not what happens. KD barely moves from his perch on the left block, even though his man, Boris Diaw, is not so great a jump-shooter as to merit stay-attached coverage in this situation.
Durant is just not used to being the guy who has to make that rotation; it's usually Ibaka's job. So what happens?
Ginobili gets to the basket with ease, uses the rim as protection and sinks a reverse layup.
The second clip is essentially the same, except Durant is on the strong side and doesn't dig down off Kawhi Leonard (probably a smart move), while Caron Butler is the one who does not rotate quickly enough to stop Ginobili at the basket.
Both of those clips show Ginobili getting to the rim with ease, but he wasn't the only San Antonio player to have a good go of it in pick-and-roll situations. According to Synergy Sports (subscription required), pick-and-roll ball-handlers shot 11-of-17 from the field for San Antonio in Game 1, while roll men shot 5-of-6.
The Spurs also made four of seven spot-up shots that were set up by passes out of the pick-and-roll. All told, that's 15-of-24 (60 percent) just on shots created directly out of pick-and-roll plays.
Meanwhile, Thunder ball-handlers shot just 6-of-17 from the field, roll men were 1-of-3, and spot-up shooters taking shots off passes out of the pick-and-roll were 4-of-8. That's a total of 11-of-28 (39.3 percent).
Much of Oklahoma City's pick-and-roll play was marked by rushed jumpers; 12 of their 17 shots by ball-handlers were jumpers, of which only three went in the basket. Not having Ibaka out there certainly didn't help, as he's the screener who is the biggest threat to score of the Thunder bigs.
San Antonio was thus free to have its bigs hang back near the paint (as it usually does) without threat of a popping or rolling screener dominating the game with his scoring.
Tony Parker was a devil in delayed transition, scoring four times on the secondary break. It's easiest to just see this in video form.
He used drag screens, engineered switches, drew overmatched defenders out of the lane and drove his way to the basket. He did whatever he wanted, and it worked. The damage wasn't limited to baskets he scored himself, as he also had four transition assists—two of which went to Danny Green, whom the Thunder could just not seem to locate on the break.
The series is not nearly over, but the Thunder have their work cut out for them if they want to take out the Spurs. Without Ibaka, the Thunder will have to alter and clean up their defensive rotations. They may have to play small more often to goose the offense, and the bigger wings sizing up to the power forward spot have to be ready to deal with responsibilities that don't usually fall on their shoulders.
OKC will need to put a crimp in San Antonio's pick-and-roll game and get its own off the ground as well. And the Thunder can't lose track of Parker, Green, Leonard or anyone else in transition.
It will be a tall task, but the Thunder aren't in the Western Conference Finals for any old reason. No, they don't have their best defender, who also acts as their release valve on offense. But they still have Durant and Russell Westbrook, as well as a unique mix of supplementary players. It can be done, but it's going to take a whole lot of work and near-perfect execution.