Boston Celtics’ success early this season can solely be attributed to its clamping, tight defense. From being fourth last season in terms of defensive ratings (105.5), the Celtics (95.9) currently leads the league in Defensive Efficiency by a mile (Golden State Warriors is far second with 102.9), according to NBA Advanced Stats.

After their first two losses, the Celtics are on an eleven-game winning streak even though they are 20th in the NBA in terms of average points per game (103.5). But make no mistake, it’s not just about solid defensive plays designed by the coaching staff; rather, the changes came from rebuilding the team structure during the offseason.

Individual contributions

Based on the latest list posted on NBA Advanced Stats (as of this writing), two players are in the Top 5 in terms of Defensive Win Shares. Starters Al Horford (0.076) and Jayson Tatum (0.072), ranked first and second, respectively. Completing the Top 10 are Kyrie Irving (0.070) and Marcus Smart (0.062), who comes off the bench, placing 6th and 10th, respectively.

But they’re not the only reasons behind the Boston Celtics’ defensive stops. Starters Jaylen Brown (0.061) and Aron Baynes rank 11th and 13th, respectively, while Marcus Morris (0.058), who just joined the team, ranks 14th. That’s a total of seven Boston Celtics players in the Top 15: all of the starters plus two players from their second unit.

Big defensive adjustments

“I think that everyone that steps on the floor is really making a conscious effort to be in the right places defensively, and to have an impact on the defensive end,” Al Horford said -- as posted on ESPN. The Boston Celtics center added that it was the mindset instituted by head coach Brad Stevens on the team, “And we're all doing it.”

According to ESPN Statistics (Hollinger Stats - Defensive Rebound Rate), Boston is currently fourth (81.4) in terms of Defensive Rebound Rating and second (53.3) in Rebound Rate.

This is a big jump from last year when they placed last in defensive rating during the fourth and fifth week.

Al Horford’s big improvement

Based on Synergy data (via ESPN), opponents are shooting a dismal 34.7 percent against Horford. What’s more is that these numbers include defensive stops with the likes of NBA superstars such as Giannis Antetokounmpo, LaMarcus Aldridge, Kristaps Porzingis, and LeBron James.

Last season, Horford ranked 69th (0.035) in terms of Defensive Win Shares.

Most notable is Boston's defensive rating when Horford is on the floor, which is 93.2, good for second behind Aron Baynes, who replaced Gordon Hayward in the starting lineup. When Horford hits the bench for needed rest, the Celtics' defensive rating goes up to 101.2, which pushes them down to seventh place.