Coming into the game, Oxtoby's side were without captain Simone Magill, Laura Rafferty, Ellie Mason and Brenna McPartlan through injury, with Rebecca Holloway suspended.
The home side, ranked 44th in the Fifa rankings, struggled to break into the final third but had multiple half chances with debutant Mia Moore firing wide and Emily Wilson also sending a shot just off target.
Oxtoby praised her side's resilience during the first leg and added she was "confident" for Tuesday's return fixture.
"When you play good teams, you're not going to have the ball as much and you're going to have to suffer," she added.
"Who are you going to be in those moments? I think we saw that, what the group is about. They stuck together. If one got beaten, the next one was in.
"We didn't necessarily want to be too expansive and push necessarily for a goal. We wanted to stay in our shape and look to counter."
