The NBA playoffs are about adjustment and exploitation; teams are constantly adjusting to opponent lineups and play calls, which will often feature combinations rarely seen in the regular season. Then they will try to repeatedly exploit weaknesses, putting the opponent in a disadvantaged position. One such example of exploiting an opponent weakness is how Houston took advantage of Dallas' lineups featuring two big men in the frontcourt, especially when Dirk Nowitzki or Amar'e Stoudemire (or both) is on the floor.
To take advantage of the Mavs' defensive liabilities up front, the Rockets lifted a play I am very familiar with from the Phoenix Suns' old playbook: the "Elbow Get." Here's a breakdown of the play and how the Rockets ran against Dallas so adeptly and won the series.