Phoenix have flown straight from China, where they had a training camp and played a game on Wednesday night, to Sydney rather than wasting time returning to Wellington first.
They arrived around lunchtime on Saturday and have set up camp at the Crowne Plaza Hotel, Coogee, ahead of the game at Campbelltown Football Stadium.
"I like the fact we’re playing an A-League side in the FFA Cup," Merrick told The World Game.
"The more high-quality games we can get, the better our preparation for the A-League will be.
"Tony Popovic is a terrific coach - he’s always got a very strong team and I’d rather play the top quality than play an NPL team.
"You’re expected to win against an NPL team and if you lose it’s a downer, and you’ve got nothing out of it, so I’m happy we’re playing Wanderers at this time of the year.
"Kosta and Gui will start the match. We’ll be fielding our strongest possible line-up. I’ve never been one to worry about injuries and try to hold players out in the pre-season.
"If you worry about injuries they occur, and the other thing is we need to play these games to find our weaknesses and strengths, so we can work on them moving forward. If you don’t find out now, it’s too late down the track."
Wellington’s trip to Beijing covered several bases. The team is sponsored by Huawei, the Chinese multinational company that is the largest telecommunications equipment manufacturer in the world, and Wellington and Beijing are sister cities.
Plus, it was an opportunity to escape the Wellington winter for a few days and train in hotter weather - the sort of conditions the Phoenix confront when they play games in Australia over the summer.
"We trained in the heat and humidity, but it wasn’t only a training exercise," Merrick said.
"We did some clinics in schools and some partnership duties with Huawei. The Mayor of Wellington was with us on the trip and we met with the local mayor.
"So when it comes to our relationship with our major partner and our sister city, it was a really worthwhile four or five days."
Wellington beat Beijing BG 2-1 in front of 20,000 people at the Olympic Sports Centre Stadium, with Barbarouses and Finkler among the stars.
Merrick said the pre-season preparation was going well, but he still has four places to fill on his roster.
"We still haven’t replaced Ben Sigmund, Manny Muscat, Albert Riera and Blake Powell, but we’ve got two more months to do that," he said.
"The rest of the squad are pretty fit and raring to go, and most of the boys got 60 to 65 minutes against Beijing.
"Gui Finkler controlled the midfield with Roly Bonevacia and Mikey McGlinchey, with Vince Lia behind them, and up front we played Hamish Watson and Kosta Barbarouses, and Kosta was man of the match.
"Gui played very well also. He just keeps possession so well and delivers the ball forward and we had several good chances against an opponent that was two-thirds through their season and were really sharp, and kept us on our toes."
Filling the centre-back and fullback spots vacated by the retirement of Sigmund and the departure of Muscat to Melbourne City is the main challenge Merrick faces.
Asked how he was going on that front, Merrick replied: "We’re very close to signing a European centre-back, but I can’t give you any more information on that or I’d have to kill you.
"I’m not close on the fullback yet, I’m still looking around. I’ve always believed you’ve got to take your time with these important signings.
"Two years ago we didn’t get Roly Bonevacia until August, so if you’re diligent and patient you’re always a chance of getting the right man."