Kevin Muscat's men were relatively comfortable in advancing to the round of 16, scoring in each half to emerge 2-0 winners at the WA Athletics Stadium.
But there was no denying the powerhouse side lacked cohesion at times, leaving plenty of room for improvement in the weeks leading up to the start of the 2014-15 league season.
"First half I think we played well and probably should have put a couple past them but second half we came out pretty sloppy and didn't really get into any rhythm, which was a bit disappointing," he said.
"At the end of the day it's always good to get the win. We're through to the next round and that's the most important thing."
Leijer welcomed the introduction of the new national knockout competition, which has provided top-flight teams with renewed focus in the months before the A-League resumes.
"Pre-season's so long, you play a lot of games that don't really mean anything," he said.
"To have two games now which are important, which means something, it's a different mindset. That's good for us. It puts us in a good position going into the first round of the season proper."
Next up for Victory is a game against NPL Victoria side Ballarat on Tuesday, with Leijer and his team-mates keen to accumulate more game-time in navy blue and white.
"It's important we get as many games in as we possibly can. I've heard it's a good facility up there, a good surface. The NPL games we've been playing so far have been great," he said.
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