SAN ANTONIO -- The biggest difference between Game 1 and Game 2 of the Western Conference semifinals between the Rockets and Spurs was not how Houston shot, or the pace, or that the Spurs hit more shots, though all of those things contributed to San Antonio's 121-96 victory Wednesday night.

The biggest difference was a team-wide loss of connection on defense, and it started with one man in particular. Let's start here. Pay attention to how far away from his assignment, Danny Green, James Harden is.

And again. This time, Green doesn't score, but you'll notice that because Harden gets beat because of a bad closeout, Eric Gordon helps down, which frees Tony Parker to knock down the shot.

The Spurs had 51 uncontested shots in Game 2, up seven from Game 1. And more important, you could tell the Rockets' connectivity on defense was not there. In Game 1 they were beating the Spurs to spots, getting up into their dribble, swiping at the ball on the catch to distract them. In Game 2, Houston relaxed and let the Spurs come at them, with devastating results. Still, Kawhi Leonard was having to hit tough shots. He was 0 of 5 in Game 1 on contested shots, per NBA.com, and 6 of 7 in Game 2. In that regard, you have to live with "sometimes the adjustment is the guy just makes more shots."

But look at Harden in relation to Green here:

And here:

And here:

Some of this is scheme. The Rockets are overloading the strong side. A lot, if not most, NBA teams do this. Send your help into the paint and recover. But Harden wasn't anticipating the kick-out to his man, and when he tried to recover, he took bad angles as shown in the GIFs above. That can't happen. When you make the Spurs beat you one on one, they only have one who can do that consistently: Leonard. At least so long as LaMarcus Aldridge remains a hot mess.

When you lose contain and then start helping, that's when they have you. When the Spurs are able to get into their comfort zone of finding open shots with ball movement and Leonard is slicing you up in one-on-one contested offense, the Spurs go from a team made of vulnerable individual personnel to a collective nightmare made of hellhounds.

And that feeds their defense. In Game 1, with the Spurs turning the ball over and forced into shots they didn't want to take, Houston ran the ball down their throats. Houston had 23 transition possessions via Synergy in Game 1. That was down to only 11 in Game 2. The Spurs got the shots they wanted, made them, and got back in transition. All of this is where they want this series to live and not where Houston wants it.

For Harden, the Rockets don't expect him to lockdown, a la Kawhi Leonard; that's not who Harden is. But staying tethered and aware off-ball is crucial so they don't have breakdowns. Harden has been better defensively this season. He's been "fine." When he was good in Game 1, it helped Houston tremendously. Whether it was his ankle, the hip he tweaked in the first quarter ("I just banged it, I'm fine," Harden said after Game 2), a lack of energy, whatever, Harden wasn't fine in Game 2.

Mike D'Antoni pointed to lapses in "determination" on defense after the game, rather than Xs and Os issues, but the two are connected.

It wasn't just Harden. Patrick Beverley, since the start of Game 1, had been daring Spurs point guards to beat him, routinely playing way off-ball, trusting he could get back and recover. It didn't hurt him in Game 1, but it hurt him big time in Game 2. Some of this changes with Parker's unfortunate injury, but Patty Mills is just as capable of burning Beverley, and is in fact faster. Beverley too has to stay engaged when his man doesn't have the ball.

Houston got the split they wanted in San Antonio. They still hung in Game 2, closing the gap to three points in the third quarter despite a lot going wrong. But they are not good enough to simply try and win this series on shooting alone. The Rockets have to get back to putting the Spurs on their heels defensively, because San Antonio's discipline, and Leonard, are ready to retake control of this series at a moment's notice.