When training camp opened in September, Brett Brown took the wealth of defensive knowledge that he had acquired during his 12 years as an assistant with the San Antonio Spurs and trimmed it down to the basics – getting back on defense, playing with energy, and keeping the ball out of the paint.

The second-year head coach’s bare bones approach has been an overwhelming success, as he’s taken a team that ranked 27th in defensive rating (107.5 points allowed per 100 possessions) during his first season with the team in 2013-14 and helped them ascend the #11 spot in that category (102.7) this year. After beginning the season 0-16, the Sixers are 3-7 in the month of December, and defense has been the thing that’s fueled the team’s recent success. Philadelphia has allowed just 98.2 points per 100 possessions this month, the fifth-best mark in the league during that stretch.

“We’re now 11th in the NBA in defensive efficiency, and we were 30th [at times last season],” Brown said proudly following shoot-around on Tuesday morning in Miami. “We just haven’t let one or two [key concepts] go, and we’ve zoomed in on them, and we have since [training camp]. I’m seeing carryover and improvement.”

In 10 games this month, the Sixers have allowed the fifth-lowest field goal percentage on shot attempts within five feet (54.7%), the fourth-lowest from 5-9 feet (36.6%), and the sixth-lowest on three-pointers (32.1%). To see what that looks like, hover over the Sixers’ defensive shot chart from 2013-14 (pictured below) and check out the marked difference on attempts in the paint and beyond the arc this month.

Some of that success in the paint must be attributed to the play of rookie center Nerlens Noel, who ranks ninth in the NBA in opponent field goal percentage at the rim (min. 8.0 FGA defended within five feet per game), allowing just a 47.1% conversion rate on those attempts.

Michael Carter-Williams has also impressed on the defensive end of the floor. In the month of December, the Sixers have allowed 2.9 fewer points per 100 possessions with him on the floor. During that stretch, he’s held his nightly assignment to an average of 8.5% below their normal contested field goal percentage on shots he defends.

But beyond defensive-minded bookends Carter-Williams and Noel, less likely members of the team have stepped up on that end as well. In fact, Philadelphia’s most effective three-man defensive combination during the month of December has been Luc Mbah a Moute, Henry Sims, and Hollis Thompson, who have held opponents to 90.1 points per 100 possessions in 78 minutes on the floor together. It doesn’t hurt that all three are above-average rebounders for their positions; that group has the best defensive rebounding percentage (85.5%) of any that has played at least 75 minutes for Philadelphia this month.

What makes the Sixers’ recent play on the defensive end even more impressive is the fact that Philadelphia’s league-high turnover rate (19.0 turnovers per 100 possessions) has actually increased during the month of December, from 18.7 to 19.4. All season long, they’ve paced at about 23.8 points per game allowed off of turnovers, nearly five points more than any other team in the league. Brett Brown imagines what the Sixers’ defensive numbers might look like if his team could eliminate some of those giveaways.

“Imagine if we could reduce our turnovers,” he said. “Our defense has been, at times, good enough to win games, but because of [turnovers] we can’t. So I think if we can not turn it over as much, which would help our transition defense, maybe we can move into the single digits [in terms of league defensive efficiency rankings].

“Our defense is moving in the direction we want.”

*Stats via stats.NBA.com, shot chart via StatMuse.com