Wellington Phoenix might be four points clear on top of the A-League table and on track for their their first Premiers' Plate but Sydney FC coach Graham Arnold feels the final five matches will sort out whether the Kiwis are contenders or pretenders.

Ernie Merrick's side have shocked the A-League this season to break clear of the chasing pack, but with a tricky run home, including two matches against Sydney FC, the Phoenix must maintain their momentum to retain their buffer.

Ahead of Sunday's clash between the two sides at Westpac Stadium, Arnold says he knows all about the pressure of being on top of the table from his time at Central Coast and reckons it carries a burden all of its own.

"Every game from now on is about pressure. It's about dealing with those situations. The Phoenix players will probably be sitting at home [on Friday night], glued to the TV, all barracking for the Mariners against Victory and tomorrow night they'll be barracking for the Wanderers against Perth Glory. That's the type of added pressure that sitting on top brings," he said at training on Friday.

"When you've got something to hold onto, it makes you desperate to hold onto it. Sometimes you can play the game before you actually do play the game - whereas we've only got to worry about ourselves.

"We're not on top spot at the moment. Our ambition is to try and get there and we've got some hurdles to go over. We've got to try and do our best to do that."

Despite questioning whether the Phoenix have what it takes to fight off the four-strong chasing pack, which includes Sydney FC, Arnold praised Wellington's season to date.

"I think it's due to their midfield – [Roly] Bonevacia, [Alex] Riera, [Mike] McGlinchey, plus Vince Lia is doing well since he's come in – and the pace up front with [Nathan] Burns and [Roy] Krishna," he said. "Fortunately for us this weekend, they're without two of those players in Burns and McGlinchey, but no doubt with Joel Griffiths and maybe [Jason] Hicks that will come in, they've still got quality players. But we've got to make sure that we're tactically ready and we'll work on that today."

The Sky Blues suffered a surprise defeat at the hands of Melbourne City last Friday night on home soil but Arnold says the players have shown a resolve to improve.

"I've seen the response at training this week. I gave them the weekend off after the Melbourne City game and on Monday the players were still hurting from the loss. But as I've said to the players before, nobody dies from a loss," he said. "I know it feels like it. But nobody dies and it's what you take out of it and it's what you learn form it. It's about moving forward straight after it.

"We talked about it, we did the review on Monday, we looked at what we did very well and that was controlling most of the game and then we touched on what we didn't do well and we've tried to fix that up. For the rest of the week, the boys have trained really well."

While the two sides will lose their top strikers due to the international break - Wellington's Nathan Burns played for the Socceroos against Germany while Sydney marquee Marc Janko has been away with Austria - the Sky Blues' natural replacement, Shane Smeltz, isn't guaranteed a start.

"Smeltzy had a bit of a calf problem yesterday and we'll assess how it is today but I'm sure he'll be OK," Arnold said. "We've got the luxury of Alex Brosque who has played naturally as a No.9. We're pretty strong in the midfield in terms of numbers as well. Bernie Ibini can play through the middle as well but Shane Smeltz, as far as I'm concerned, will be fine."

Defender Jacques Faty has been out recently with a hamstring strain but trained strongly on Friday and will be pushing for selection to partner first-choice centre-back Nikola Petkovic.

"We've got a lot of players that have been in the deep end of seasons and they're looking forward to the weekend," Arnold said. "Jacques is available. He's trained extremely well the last two weeks. I held him back last week because with hamstrings, you want to leave an extra week, but Jacques is in the squad for sure this week."