Lynne Sladky/Associated Press

The Brooklyn Nets entered the season expecting to be a top-10 defensive team for a number of reasons but mostly because the presence of Kevin Garnett on a roster has essentially guaranteed that status for a while now.

For the first two months of the season, though, the Nets were as sieve-like on defense as any team in the league. Through December 21 (the day Brook Lopez was declared out for the season), Brooklyn's opponents registered a 106.4 offensive efficiency, the third-worst mark in the league, according to NBA.com.

Soon after that, Jason Kidd switched to the new "long ball" starting lineup, and the Nets defense turned around. The Nets had the NBA's 12th-best defense after December 22, largely due to the lineup and strategy tweaks made in the wake of Lopez's season-ending injury.

On Tuesday night against the Heat, though, that improved defense was nowhere to be found. Miami scored an astonishing 107 points on only 84 possessions in Game 1, good enough for a 127.4 offensive efficiency.

Where Miami was able to hurt Brooklyn the most was with spot-ups and off-ball cutting action, as the Nets were a step slow and late with their rotations all game long.

The Nets were one of the worst teams in the league at limiting spot-up opportunities for their opponents this season according to Synergy Sports (subscription required).

Brooklyn's opponents shot 40.9 percent from the field and 39.0 percent from three while scoring 1.03 points per play on spot-ups, making Brooklyn the third-worst defense in the league against spot-up plays—and Miami was able to free its shooters for open looks all night.

A particular look that gave the Nets a whole lot of trouble was one where the Heat used LeBron James as the screener in a pick-and-roll before popping out into open space for a post-up on the deep wing. The two plays in the video below are essentially mirror images of each other, and each ends with a corner three on opposite sides of the floor.

In the first clip, LeBron runs a side screen-and-roll with Mario Chalmers on the right side of the floor, and as Chalmers comes around the screen, both Deron Williams and Shaun Livingston jump his dribble. While this is happening, Shane Battier runs along the baseline from the right corner to the left corner. This doesn't look important at first, but it will be soon.

Because Williams and Livingston are jumping the ball-handler as he comes around the screen, the responsibility for cutting off LeBron's lane to the rim falls on Pierce, whose man was in the strong-side corner. Pierce overloads the strong side to deter LeBron's drive, allowing Livingston to recover back to LeBron on the deep wing.

That leaves Garnett alone on the weak side, where he's responsible for covering both Chris Bosh and Battier. Garnett plays it correctly, splitting the difference of the space between the two shooters, and when Bosh flashes open, LeBron hits him with the pass.

That forces KG to commit to stopping Bosh's jumper, so Bosh makes the correct extra pass to Battier in the corner for three before Pierce can recover all the way across the floor.

The second clip, again, is a mirror image. This time LeBron and Chalmers go into their side-screen action on the left side of the floor. Once again two men jump out at Chalmers as he comes around the screen, and Chalmers dishes to LeBron on the deep wing.

LeBron's all alone on the baseline, which means Mason Plumlee has to come screaming across the court to cut off his driving lane. Plumlee's rotation means Marcus Thornton has to bump down and pick up Chris "Birdman" Andersen underneath the rim, which leaves Joe Johnson to patrol Battier and Ray Allen on the weak side by himself.

Johnson is well-positioned between the two shooting threats, and once again LeBron hits the man on the swing as soon as he flashes open. Battier is already making the touch pass to Allen in the corner before the ball even gets there, and there aren't many more automatic baskets than a Ray Allen open corner three.

While those were plays where the Heat took advantage of schematic tendencies by deliberately forcing the Nets into particular rotational contortions to open up a specific shot, there were also times when Brooklyn's defense just broke down on its own for no reason at all.

Take this Chalmers basket in the first quarter. The ball gets entered to LeBron in the post, so, as is typical of many teams, all Nets immediately train their eyes on him.

via TNT

Pierce again abandons his man as he cuts from one side of the court to the other and overloads the strong side, hoping to discourage LeBron from driving baseline and overpowering Livingston. Williams shades all the way off Chalmers at the top of the key (off screen) to the point where both of his feet are eventually in the paint, and Johnson sinks all the way down off Battier and into the paint as well.

They all start pointing at each other, gesturing about which player should pick up which man because they're all so concerned with stopping LeBron. While Williams has his back turned, Chalmers simply knifes right through all of them, and nobody picks him up because everyone's too busy pointing and positioning himself to stop LeBron.

Notice how KG didn't even try to stop Chalmers at the rim. That was not his only blown rotation of the game. Garnett played a Wade-Bosh third-quarter pick-and-roll as badly as I've ever seen him play the action in my basketball-watching life.

This does not look anything like the same player who smothered Kyle Lowry coming around a screen on the last play of the Nets' Game 7 victory over the Toronto Raptors on Sunday.

Garnett doesn't jump out high enough to blitz Wade coming around the screen, and he doesn't really drop back to contain Wade near the elbow either. Garnett at first stays attached to Bosh as he rolls through the paint, but he abandons that idea in a halfhearted attempt to stop Wade from getting an easy layup. None of it works, and Wade gets two fairly easy points.

That's nothing compared to the lazy rotation we see here from Joe Johnson later in the quarter, who basically just watches as Bosh gets a free dunk.

This time Garnett aggressively jumps out at the ball-handler coming around the screen, so Bosh slips his roll to the rim. Johnson already has a foot in the paint before Bosh even starts rolling to the rim, and he still doesn't manage to make it to the middle of the paint in time to give anything more than a token "contest" of Bosh's dunk.

These are just a few of the issues the Nets had in Game 1, but there were more. Most notably, the transition defense was a mess, and there were too many times where simple cuts resulted in unguarded players netting easy layups.

Miami scored only 11 transition points, but that is in part because the Heat had only four steals, despite the Nets turning the ball over 11 times. If more of Brooklyn's turnovers were of the live-ball variety, that number would have been significantly higher. As it is, the Nets left Allen and Bosh wide open on the secondary break multiple times, often after made baskets.

Those are inexcusable breakdowns that absolutely can't happen if the Nets expect to compete with or beat Miami in a seven-game series.