Phoenix has just one win in its last five matches, slipping off the pace after sitting top of the table in mid-March for the first time in the club's history.
Coach Ernie Merrick is supremely unconcerned.
"It's more about confidence than anything else, and this team are very confident," he said after Saturday's final training session in Wellington.
"This is finals football, it's sudden death. We've got to take the game to them, and we've got to play our brand of football."
City has also struggled in closing out the season, with just one win from its five latest outings, but Merrick says its recent form isn't really relevant.
"I haven't focused on them at all, but they've obviously got a quality team with good players - they haven't had a great run-in results-wise, but that means nothing."
Finals football is all about adjustment, and how quickly teams can tweak their structures and tactics, he said.
"It's more intense, players are time-stressed and decision-making's got to be rapid.
"It's the same, in that the structure doesn't change a lot, but it's different in that it's quicker."
Phoenix welcomes back goalkeeper Glen Moss, who missed last week's 2-1 loss to Sydney FC with a minor knee strain, and although Merrick was cagey when questioned about his starting line-up, there seems no reason to expect major changes.
Woes with missed penalties aside, Merrick was satisfied with the way Wellington took to the game to second-placed Sydney FC, with Roy Krishna, Kenny Cunningham and Alex Rodriguez all making their impact off the bench.
"We didn't get into key areas to get our shots off, but I thought the football was good, so there's not going to be many changes from last week."
With his team fizzing in an intense final training session, and with the promise of a 15,000-plus crowd at Westpac Stadium on Sunday, Merrick is happy his team is where it needs to be to win and set up a semi-final clash away to Melbourne Victory next week.
"It's the culmination of a full season's hard work, good results, and we've earned this spot," he said.
"If we'd got our game right against Sydney, we might even have finished in the top two. We've missed out on that - we're not going to miss out again."
