The Tritons fall to 0-3-3 overall and 0-2-2 in the California Collegiate Athletic Association, while SSU improves to 5-1 overall and 3-1 through league play.
The Seawolves outshot UCSD 13-7 across the 90 minutes of play, with Tritons' goalkeeper Jesse Brennan recording five saves in the losing effort.
The match tally remained 0-0 until the 44:18 mark, when SSU's Kelly Davila sent a header past Brennan after receiving a cross from Erick Delgado.
The Seawolves stretched their lead to 2-0 in the 66th minute, as Nico Spann and Taylor Varnadore threaded one-tough passes into the box for Ebby Lombardi, who placed a shot to the back of the net.
The final score of the match came roughly five minutes later with a cross by Trevor Hurst into the box found Spann, who sent the ball to the left of a diving Brennan.
Shane Micheil and Scott MacBride led the Tritons' offense in shots, with two apiece.
UCSD continues its road swing on Friday with a 3 p.m. match against Cal State Monterey Bay. That contest is followed with an 11:30 a.m. game Sunday at San Francisco State.