I don't see MIN as talented enough or having enough emotional fortitude to win 4 straight vs. DAL. I see these teams as too evenly matched for that to happen. The only exception would be if Luka gets hurt or something like that, which may not be all that much of a stretch.
The way Luka has to play, in order for them to win, results in him taking a beating. He has been taking that beating every other day or so for the last several weeks. If they can close this out, he can get some rest, but most of the key Celtics players are going to be much fresher, much less beat up (Porzingis being the exception, and he might be fine, you just don't know).