The Kildare, Ireland, native started the scoring for the Phoenix in the 18th minute, taking a long ball from Markus Skraastad, stopping the pass on a dime and firing low and left past UC goalkeeper Ahmed Ghatwary.
Skraastad played another beautiful long pass in the 27th minute, this one down the right side. Bakary Bagayogo raced onto the ball and chipped it past Ghatwary. His shot was knocked away from the goal line by UC defender Brandon Scherr, but it went right to McNamara, whose shot bounced off Scherr, who was sprawled across the goal line.
It was the sixth and seventh goals of the year for McNamara, who has seven goals and four assists in nine matches this year.
Cumberland will play at 13th-ranked Campbellsville on Tuesday and 11th-ranked Lindsey Wilson on Friday.