The 4-0 win was the first time Manly has defeated Blacktown at Gabbie Stadium since 2001.
It was Blacktown City who started the stronger and Daniel Wilkinson put in an early cross to Chris Bedzo who headed the ball wide of the far post.
Then debutant Agyei Akwasi interchanged with Bedzo on the edge of the penalty-area and played Matthew Lewis into a strong position, but Brad Swancott blocked his path in the Manly goal area.
Manly started applying pressure on the home side in the 10? minute and it paid dividends. 4? minutes later, after it looked as though the Demons had avoided danger, the ball fell to Robbie Cattanach a long way from goal.
His shot beat Ivan Necevski at the far post and struck the back of the net. The effort had come from twenty-five yards out and was struck along the ground with maximum effect.
Four minutes later Cattanach was almost presented another chance but his shot was poor. It was a mistake he learnt from, but his opponents did not.
In the 27? minute Blacktown?s Paul Karbon turned inside and laid the ball into Cattanach?s path and as Ivan Necevski advanced he slipped, leaving Cattanach to chip over him and into the back of the net.
Six minutes later Michael Williams could have played Cattanach into space on his left but instead played Craig Midgely on his right and Midgely had his path blocked by Necevski.
Then Karbon repeated his mistake again, but this time it was Midgely who pounced. As he advanced though, he shot too early and Necevski made an easy save.
A minute later a through ball put Joey Schrippa into space but his shot was turned around the near post by Necevski.
In the 38? minute the local crowd thought that they may have had a penalty when Jordan Simpson went down in the area but the only thing Blacktown City collected was a yellow card for diving.
Three minutes from half-time Cattanach almost completed his hat-trick after he smashed a shot past Necevski and onto the post after good lead-up from Midgely on the right. Seconds from the break Bedzo had a half opportunity to grab a goal but Roberto Hamad blocked the chance and it came to nothing.
Immediately after the break, a head clash between Graeme Forbes and Bradley Groves saw Groves taken to hospital with a large gash on his head and concerns over a possible neck injury.
In the 55th minute Agyei Akwasi had the ball in the Manly area but rather than take an early shot he stepped back across the defence and he was shut down.
Blacktown was playing better football and Manly had drifted from the task at hand but in the 57? minute Cattanach put in a cross from the right and Midgely headed it towards goal – Necevski saved easily.
Two minutes later ? at the other end – Bedzo and Akwasi both had shots denied by Swancott.
In the 63? minute, a calamity almost occurred again as a clearance from one defender deflected off a team-mate into the path of Cattanach once more. Bizarrely, his shot beat Necevski but bounced off a third Blacktown City defender and back into the hands of the Blacktown City goalkeeper.
In the 68th minute Manly saw a shot from Midgely saved brilliantly by Necevski but his parry fell for Cattanach whose effort was also saved by Necevski.
The ball was then quickly played away by Bedzo and he played it into Jordan Simpson who saw Brad Swancott trip-up on one of his own defenders as he advanced towards him. Simpson?s shot was blocked on the line by another Manly defender and Leo Carle put the follow-up effort on the wrong side of the post.
Two minutes later Swancott saved from Simpson superbly.
In the 77? minute Michael Lloyd Green put the nerves of his team behind him as he put the ball in the back of the net after strong lead-up work by Cattanach.
In the 85? minute Ken Chun at the far post put a cross wide of the target when it was possibly easier to score than miss.
After all his efforts it seemed Cattanach?s desire for his second hat-trick of the season was to be denied after Necevski saved a late effort from a free-kick. However, one-minute from time Cattanach pounced on a long ball and fired it past Necevski into the far side of the goal for his third of the afternoon.
After the match Ken Schembri was disappointed with the overall display from his team:
?We don?t take our chances and gifting the opposition soft goals when we are struggling is a formula for no success. We opened well but they were clinical with their chances.?
As for Phil Moss he was pleased to have come away with such a good result:
?I was reasonably happy with our first-half. In the second-half it showed we had to play an extra Cup match mid-week and we took our foot of the accelerator. I am delighted for Cattanach, he rose to the challenge today. We have tried some new things today in our play and it worked well which was pleasing.?
Blacktown City Demons 0
Manly United FC 4 (Robbie Cattanach 14?, 26?, 88?, Michael Lloyd-Green 76?)
Venue: Gabbie Stadium
Referee: Atila Stibinger
Blacktown City Demons: 1. Ivan Necevski; 3. Paul Karbon, 4. Daniel Wilkinson, 6. Ken Chun, 17. Graeme Forbes, 13. Ben Ellis 18. Jesse Pinto, 25. Jordan Simpson (15. Luke Austin 82?), 29. Matthew Lewis (11. Nicholas Ruoco 75?), 8. Chris Bedzo, 19. Agyei Akwasi (10. Leo Carle 64?)
Substitutes Not Used: 20. Matt Nemes, 14. Gavin Forbes
Yellow Cards: Jordan Simpson 38? Graeme Forbes 87?
Red Cards: Nil
Manly United FC: 1. Bradley Swancott; 3. Andrew Mailer, 4. Roberto Hamad, 5. Pascal Julliard, 6. Bradley Groves (12. Michael Lloyd-Green 49?), 8. Michael Williams, 9. Robbie Cattanach, 11. Craig Midgely (33. Chris Payne 68?), 16. Joey Schrippa (15. Cameron Jones 82?), 18. Beau Busch, 19. Richard Williams
Substitutes Not Used: 21. Luke Femia, 7. Ashley Ryan
Yellow Cards: 73? Richard Williams
Red Cards: Nil
3 – Robbie Cattanach (MU)
2 – Craig Midgely (MU)
1 – Joey Schrippa (MU)
-By Stuart Jones