Lander, which outshot the Pacers, 9-3, improves to 3-6-1 overall and 2-3-1 in the PBC, while USC Aiken drops to 3-9, (1-5).
After a scoreless first half, Walker gave the Bearcats a 1-0 lead on an penalty kick at 71:42.
The Bearcats extended the margin to 2-0 at 77:26 when Ellinger scored off an assist from Sara Flores.
Lander had four corner kicks, compared to USC Aiken’s two.
Bearcat goalkeeper Megan Wiley had one save, while Karin Cadwalader recorded six saves for the Pacers.