For Singapore it's a chance to further refine squad training ahead of the Asian Games in Incheon, as well as doing some early preparation for November's Suzuki Cup.
Papua New Guinea (PNG), meanwhile, are focusing on the 2015 Pacific Games which they will be hosting.
Rufer, the 51-year-old former Zurich, Grasshoppers and Werder Bremen striker, explained that for him it's a bit of a journey into the unknown.
"You could say we are going to approach this game quite defensively," he admitted candidly at the pre-match press conference held at the Bugis Village Hotel on Friday afternoon.
"Half the players have not played for the national team before and this is my first game in charge in an international match.
"We've had some local friendlies, including some in Queensland, but this is the first international for us since I came in."
The Papua New Guinea coach also explained the make-up of his squad, with the majority of the team made out of players plying their trade in their local league.
"Some of the players are playing in New Zealand and four of them are competing in Australia," he said.
"Brad McDonald, for instance, is being released by Central Coast Mariners, but we still have to sort out his passport. He is eligible for PNG on his mother's side.
"Many of our players come from the local Port Moresby club, Hekari United, who are the 'Real Madrid' of the nation, winning seven titles in a row from 2006-7 to 2013.
"David Muta (who was at the press conference) is our captain and he plays for them too.
"Originally, we'd hoped to play some warm-up games against S.League teams and then take on the Singapore national team, after holding a training camp here, but that fell through, unfortunately.
"We don't know what to expect from Singapore so we'll be treading carefully."
Aide Iskandar, standing in for the indisposed Singapore coach, Bernd Stange, fielded questions mostly about Singapore's Asian Games preparations.
"We'll try to give a few boys a run, tomorrow" he said.
Stange, who has a fever, has been lying low and maintaining his distance from the players and coaching staff to avoid anyone else falling foul of his own symptoms .
"I'm not sure when he'll be back," Aide said.
"He is resting and for the time being I guess I'll be the one conducting the training.
"We'll have to wait and see if he is able to take his place on the bench later."
The Singapore squad had a solid hit-out on the lush Hougang Stadium pitch on Friday evening and coach Aide reported that everything went smoothly.
"No knocks to speak of, from what I can see," he said, before going on to explain why some players had not showed up for training.
"I gave Safuwan (Baharudin) and Faris Ramli a couple of days off.
"They'll be back for the Hong Kong match."
Meanwhile the PNG players had their first look at Singapore pitch conditions and coach Rufer seemed satisfied.
"My only concern is if it rains," he said.
"The pitch is good, but the players didn't bring screw-ins (long studs) with them as they don't play on surfaces like this at home."
The visitors session was mostly conducted by Rufer's assistant, Serbian-Australian Milan Miric, who is the Papua New Guinea Academy coach.
The PNG players look like a strong physical side and were full of running.
They are likely to face a Singapore defence marshalled by Baihakki Khaizan and Afiq Yunos, with the flankers drawn from the ranks of the Courts Young Lions, players like Fadli Kamis and Al-Qaasimy Abdul Rahman.
Fringe players such as newcomer Suria Prakash and promising teenager Adam Swandi showed up well, playing for the bib-wearing 'opposition'
Likely starters, Sahil Suhaimi and Fazrul Nawaz, were doing much of the attacking work in the spirited half-pitch game that rounded off the session.
"It was our only session before the game and it went well," Aide said.
Image Credit: Abel Khoo/Football Association of Singapore