Gary van Egmond has warned his Newcastle Jets side will have to significantly improve on the performance from their 2-0 loss to Perth Glory to make the A-League finals.
The Jets' impressive run of form, which had seen them win their previous three games, came to a crashing halt at nib Stadium on Saturday when they were thoroughly outplayed by Perth.
Goals to Adam Hughes and Billy Mehmet either side of half-time inflicted a costly loss on the Jets, who will finish the round outside the top six if Sydney wins at Adelaide on Sunday.
Ahead of Sydney's game, Newcastle (28 points) were two behind fifth-placed Heart with a gap of one over the Sky Blues and three over Melbourne Victory.
Van Egmond said he was frustrated by his team's performance against Perth and made it clear they had to improve to see off the challenges of Sydney and the Victory to make the top six.
"We're under no illusions of how difficult it will be for us to remain in the top six," he said.
"We know that we have to be better than what we were today and we can be better and we've shown that."
"We just have to become more consistent."
"A lot of times our decision-making from defence was probably not the best and they're areas that we have to get better."
"I felt we were probably second to the ball, especially on the back end of the second half ... unfortunately we weren't as good as we could've been."
The Jets appeared to miss influential midfielder Jobe Wheelhouse, who was absent due to an adductor tear, but van Egmond was reluctant to use that as an excuse.
"I think we missed him but the whole team is not built around one player," he said.
"If you're going to achieve anything in this league you have to have some depth."
The coach said Newcastle would have to 'wait and see' if Wheelhouse could return for Friday's vital home match against Adelaide but didn't rule him out.
He indicated there was also some hope of Ben Kantarovski returning in time from the Olyroos' fixture in the United Arab Emirates to take part against United.
"It's pretty tight with Ben Kantarovski coming off Olyroos duty so we'll just see what type of game time he gets. We'll assess it during the week," van Egmond said.
After playing Adelaide, Newcastle face Victory on the road and then host Gold Coast.