Earlier this season, I took a look at the Celtics defense and noted that, measured by Defensive Rating relative to league average, Boston was playing the best defense since 1973-74, when the league began tracking turnovers, allowing us to calculate per-possession defensive ratings. The Celtics have slipped slightly from that lofty perch, but not far. Their Defensive Rating is now 8.8 percent better than league average, which would rank them second in NBA history behind the 2003-04 Spurs, who were 9.3 percent better than league average.
http://www.basketballprospectus.com/art ... icleid=235
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