Why Do Spurs Lose?

I sense a strange trend developing with this year's San Antonio Spurs.

Ok, there's not a lot of data to go on, since the Spurs have lost just 5 games out of 24, but look who they've lost to:

11/5 at Dallas, 84-103
11/12 at Washington, 95-110
11/25 vs Chicago, 99-106
12/10 at Atlanta, 84-94
12/18 at Oklahoma City, 76-89

What do these games have in common?

• 4 out of 5 were on the road. No surprise there.
  
• All were played on the second night of back-to-back games. No surprise there, either.
  
• 4 out of 5 games were against teams with losing records. Now that's strange.

Six days and counting until the Christmas Day showdown against the Pistons, who are presently the best team in the NBA.