An empty scoreboard at half time prompted striker Reece Vittiglia to take advantage of a perfectly delivered cross from Dean Evans in the 63rd minute and smash the ball past Armadale keeper Luke Radonich.
While it was not as high scoring as Perth SC would have liked, coach Taki Nicolaidis said three points was the objective and it was achieved.
"Im pleased with the result but it wasn't one of our most clinical performances," he said.
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READ NOW"The expectation was to come away with a decent win but sometimes you have to win ugly.
"You're not going to go through 22 games of the season and play at your best every week, and this week was one of those weeks where we ground out the result - in the end, it's still three points."
The first attempt at goal came 15 minutes into the match, Mark Pritchard belting the ball from inside the box.
Josh Wilkins had a chance at goal 10 minutes later, only to have it rebound off the post to Frank Furfaro who then shot a low strike which landed in the keeper's hands.
Five minutes to half time, Wilkins and Vittiglia tried to break the empty score board, but Radonich stood strong and prevented the half time advantage.
"Had one of those early chances gone in, that could have opened the flood gates, but it's still 1-0 and three points," Nicolaidis said.
"I thought our pertinence and midfield were pretty strong all game. And defensively we weren't too bad as well, just a little bit wasteful in the last third."
Vittiglia's goal was his first since round 16 against Balcatta.
"It's been a few weeks since Reece found the back of the net and Im happy for him, he's a decent player," Nicolaidis said.
"It's nice for players who have been on the outer for a little while to find the back of the net and that's what he's good at.
"It was a great run by Deano (Dean Evans) in the first place and the delivery, which was lacking in the first half, was a decent ball in and Tiggs (Vittiglia) was in the right place at the right time and finished it off."
Perth SC are in third place on the NPL ladder and eagerly awaited the result of the top of the table clash between Floreat Athena and Bayswater City on Sunday, with hopes to jump into second place should Floreat lose - hopes that were dashed when the game ended in a 2-all draw.