When looking to identify the best defensive team in the league, one should look no further than the franchise that set the contemporary standard.
Beginning in the 2007-08 season, the Boston Celtics—with the expertise of defensive engineer Tom Thibodeau—redefined the way that NBA teams play defense. Those Celtics were supposed to lean on the collective offensive brilliance of Kevin Garnett, Paul Pierce and Ray Allen, yet Thibodeau and Doc Rivers imparted a defensive system that to this day ranks as the NBA's finest.
Loading the Strong Side
One of the fundamental tenets of the Celtics' defense is so amazingly simple that it's a wonder coaches hadn't leaned on it heavily since the evolution of the NBA's illegal defense rules. Rather than run a strict man-to-man defense or a true zone, Boston's default setting matches up and shifts additional pressure to the strong side of the court.
As the ball rotates, so does the pressure. Dedicating an extra defender to the ball side of the court makes it that much more difficult to dribble penetrate, all while inviting opponents to make risky cross-court passes that can easily be picked off.
The Celtics ranked second in the league in opponent's turnover rate last season for a reason; once the initial defensive front denies dribble entries, post sequences and pick and rolls alike, flustered opponents often do the Celtics a favor with their miscues.
An Invaluable Anchor
But none of that would be possible without Garnett—the unquestioned leader of the Celtic ranks and one of the greatest all-around defenders the league has ever seen. That KG has been able to preserve his mobility through age 36 is pretty miraculous and has lengthened a competitive window that was once thought to have already closed.
Garnett shifts between power forward and center effortlessly, and goes about defending both positions with length, lateral quickness and guile. Neither diminished athleticism nor frequent changes in Boston's rotation have prevented Garnett from consistently making an incredible defensive impact.
The circumstances of the last few seasons would seem to be working against the future Hall of Famer, but his ability to slide and contest all over the floor makes him an invaluable focus of the league's finest team defense. Every Celtic leans on Garnett on the defensive end, and seldom does he disappoint.
An Understood Concession
Many dimensions of basketball strategy exist in the form of a give-and-take; try as teams might, they can't have it all, and the Celtics have done well to concede one element of their performance in the name of defensive stability.
Boston regularly finishes among the worst teams in the league in offensive rebounding, and in the 2011-12 campaign they managed to wind up dead last. Some of that can be attributed to personnel, as Garnett—the team's best rebounder—spends many offensive possessions 15 feet away from the basket.
But Doc Rivers has also willfully given up the pursuit of offensive rebounding in the sake of playing better transition defense—a must for a team with such an effective defensive system. The extra seconds that Boston steals by not fighting for an offensive board allows them to establish position to defend for a full defensive possession, therein keying their most substantial advantage.
Conceding a weakness to build on a strength isn't always a prudent strategy, but it's done plenty of good for the Celtics' defensive front over the last five seasons.