Examining C's league-best 3-point defense

BOSTON -- The Boston Celtics rank first in the league in 3-point field goal defense, allowing opponents to shoot just 31.9 percent beyond the arc this season. Asked about the reasons for his team's success, Celtics coach Brad Stevens couldn't resist a joke targeting one of his team's most glaring weaknesses.

"The cynic in me would say when we throw the ball to the other team, they lay it in usually instead of shooting a 3," cracked Stevens, highlighting Boston's turnover woes that have created easy points for the opposition this season.

But Stevens admitted that defending the 3-point line has been a focus for his team.

"I think we’re doing a pretty good job of identifying guys that make shots at a high rate... and we’ve been guarding the 3-point line good as a result," said Stevens.

The Celtics rank seventh in the league allowing opponents to shoot 35.6 percent on corner 3-pointers (the league's most efficient shot) and third in the league as opponents shoot 31.3 percent on all 3-pointers above the break. Not surprisingly, the splits shows a Boston team that defends the line even better in wins (33 percent corner; 28.1 percent above the break) than in losses (36.8 percent corner; 32.7 percent above the break).

Dig a bit deeper into the advanced numbers and Boston ranks second in the league allowing 0.946 points per 3-point attempt (non-halfcourt heave variety), according to Synergy Sports data. Only the Knicks have been better (0.916 ppp), while the league average hovers around 1.071 points per play. For comparison's sake, those struggling Nets are last in the league allowing 1.168 points per attempt.

Maybe the biggest secret to Boston's success is this: The Celtics have discouraged teams from taking 3-point shots as opponents average a league-low 16.2 attempts per game beyond the arc. Some of that might be a product of the easier buckets that Stevens joked about, but it also suggests Boston is doing a good job of getting out to the perimeter to either deny 3-point attempts or at least forcing the opposing shooter to move inside the arc for a lower-efficiency shot.

That's a staggeringly low number when you consider a team like the Philadelphia 76ers resides at the other end of the spectrum allowing 27.5 3-pointers per night. The league average settles around 20.5 3-point attempts per game.

A closer look at Boston's 3-point defense by shooting zone:

Celtics defense

The one lingering question is who, individually, has been best at defending the 3-point stripe for Boston this season? Here's a glimpse at the totals through 17 games with help from Synergy Sports data, among Boston's top rotation players:

Individual 3-point defense

Players like Bradley and Crawford likely get caught rushing out to defend players left open on the perimeter, partly skewing their overall numbers. But what jumps out about this data is the job that Boston's bigs have done in being able to defend the 3-point line. Having versatile and athletic bigs is clearly helping the Celtics limit 3-point opportunities from opponents.

Now if they can just fix those turnovers.