Real or not: The defense behind the NBA's five most surprising starts

The Minnesota Timberwolves and Oklahoma City Thunder are battling near the top of the Western Conference. Which start is more sustainable? Photo by Jordan Johnson/NBAE via Getty Images

As the NBA season nears December, there are a number of surprise stories at the top of the standings, highlighted by the draw for the knockout phase of the inaugural in-season tournament.

In the East, the Orlando Magic would have home-court advantage in the playoffs if the season ended today, while the Indiana Pacers -- the first team to book a spot in the in-season tournament quarterfinals -- would be the No. 6 seed in the East, after both missed the postseason last year.

Out West, the Minnesota Timberwolves and Oklahoma City Thunder are the conference's top two teams after both were in the play-in a year ago. And the Houston Rockets have surged from the league's second-worst record to above .500, good enough to make the play-in if the season ended today.

For most of these teams, defense has been a winning formula. Houston, Minnesota and Orlando boast three of the NBA's top four defensive ratings, while Oklahoma City is not far behind at No. 7. By contrast, the Pacers are one of the league's worst defenses on a per-possession basis but have managed to outscore opponents with the most efficient offense in NBA history to date.

Which of these surprise stories is likely to continue beyond the conclusion of the in-season tournament? And which Cinderellas might see their coach turn back into a pumpkin? Let's break down their chances using advanced stats.