Daman Starring added 12 points and five assists for the Anteaters (6-10, 3-1 Big West).
Harrison Dupont scored 11 points for UC Davis (1-14, 0-3), which lost its 11th straight game. Eddie Miller had 13 rebounds.
UC Irvine opened the second half with a 10-2 run to go on top 44-33, then built the lead to as many as 17 points down the stretch.
The Anteaters led 16-5 in the early going, but UC Davis used a 12-1 run later in the half to tie it at 24. The Aggies pulled ahead 27-26 on a 3-pointer by Tyrell Corbin with 4:10 left in the half, but McNealy answered with a 3 of his own as the Anteaters took a 34-31 lead into the break.