NBA Power Rankings: The races and players we're watching closely in the final week

The NBA play-in tournament races -- more importantly, the races to stay out of the play-in -- sure make the regular season's final week compelling. The Miami Heat took a huge step in securing their top-6 seed -- and avoiding a spot among Nos. 7 to 10 -- by defeating the seventh-seeded Boston Celtics on Sunday. The teams will meet again Tuesday night.