Porter connected on 7-of-10 from the field and D'Vauntes Smith-Rivera added 14 points as the Hoyas (13-4, 3-3 Big East) used a tough defense to limit the Fighting Irish to just 35 percent shooting.
Smith-Rivera blunted a Notre Dame second-half comeback try with a 3-pointer and Georgetown then went on an 18-0 run to turn the contest into a rout.
The Irish (15-4, 3-3) got 13 points from Jerian Grant but it wasn't enough to prevent their third loss in four games.
Pat Connaughton added 12 points and Jack Cooley contributed 10 with 10 rebounds in the setback.
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