Charles Barkley made a very prescient comment on TNT after game 2 of the Suns and Mavs series. He said superstars step up in the biggest moments of games. Paul has done that frequent during both the series with the Pelicans and the Mavs. Although Luka has had 2 incredible offensive games vs the Suns, he hasn't been able to carry the Mavs to victory in either game.
Probably too simplistic of an analysis, but the fact remains that Paul has been an incredible closer during the playoffs this year.