Nestling among the snow-capped Campsie hills, Celtic's picturesque Lennoxtown training complex is an image of tranquillity as Scott McDonald and Shunsuke Nakamura finish their morning session. Yet even as the Scottish champions' Australian striker and Japanese midfielder joke amiably in the midwinter sunshine, both are well aware they will soon be pitted against each other in a passionate and potentially decisive battle on the other side of the world.

A week tomorrow, McDonald's Socceroos will be found limbering up for a crucial FIFA World Cup™ qualifier in Yokohama, a city in which his club colleague just happens to be a bona fide icon. This eastern metropolis is Nakamura's home town, after all, and it is here, to his first club Yokohama Marinos, that he has pledged to return once his Celtic contract expires.

McDonald is just as aware that the darling of the local fans is also an inspirational and talismanic figure for his Japanese colleagues, with the team's humbling recent defeat in Bahrain widely attributed to his absence. Yet ahead of this key game, it is Australia - with three wins from three - who occupy the Group 1 driving seat, and McDonald is aiming to ensure they stay there.

As he told FIFA.com: "A draw would probably suit us as we're two points clear of Japan at the moment. But the Australian mentality in any sport is to always go for the win. I've had a fair amount of banter with Naka over this match and I'm fortunate that I have a really good relationship with him where we can have a proper laugh about it.

I promise I won't kick Scott because if I do he might get injured! We have the Rangers game a few days later and that would not be good for the team.

Nakamura vows to go easy on McDonald.

"I've certainly told him that I'll be looking out for him on the pitch and telling our lads what he's all about. That said, I don't expect I'll need to tell them too much because I think that anyone who knows their football has an immense respect for him. Our guys have played against him in the World Cup and the Asian Cup recently, so they all know what a dangerous player he can be and how important he is to the Japanese. He'll be a big danger to us, there's no doubt about it, but hopefully we can keep that left foot of his quiet."

Regardless of who prevails next Wednesday, it promises to be a week to remember for McDonald and Nakamura. Given their schedule, it could hardly fail to be. After all, within 72 hours of locking horns in this crunch qualifier, the Celtic duo will be reunited in the green-and-white hoops and pitched into the cauldron of an Old Firm derby. With this always-compelling showdown all the more intriguing for the fact that a Rangers win would see the Ibrox club leapfrog their old rivals at the top of the table, Nakamura reflects with a smile on the importance of emerging from Yokohama unscathed.

Looking ahead to Australia's visit, he said: "It is a big match for both countries and expectation is very high in Japan about the World Cup. But I promise I won't kick Scott because if I do he might get injured! We have the Rangers game a few days later and that would not be good for the team. I might have a word with our defenders about his style of play, but that will be it."

Nakamura has witnessed first hand McDonald's rapid rise since moving from Motherwell in 2007 and admired the goalscoring knack that saw the bustling little striker end his debut season at Celtic Park as Scotland's top scorer. Yet although this feat earned the 25-year-old a regular Socceroos starting slot for the first time, he has yet to replicate his club form at international level and is still awaiting his first goal.

With Celtic, however, he has at least earned himself something of a reputation as a scorer of vital goals, from a 90th-minute winner against AC Milan in last season's UEFA Champions League to his double in a 3-2 victory over Rangers that all but secured the Scottish title. Add to that his brilliant lob against Manchester United in this season's Champions League and you have a player rightly confident of rising to the big occasion.

I'll be looking out for him on the pitch... He'll be a big danger to us, there's no doubt about it, but hopefully we can keep that left foot of his quiet.

McDonald on facing Nakamura.

"When a big game comes around, I do feel that I'm the kind of guy who can step up to the plate and score a vital goal," he said. "And this match certainly falls into that category. I feel it's about time I broke my duck for Australia and there would be no better time to do it than in Yokohama."

For McDonald, who watched from home as Australia made history at Germany 2006 - "I didn't deserve to make that squad," he admits - the prospect of playing a more active role in South Africa is hugely exciting. Yet this is not a player entirely without pedigree at world level.

Ten years ago, he was an integral part of the Aussie team that came within a penalty shootout of beating Brazil in the FIFA U-17 World Cup final, and four years later he starred as revenge was exacted on the Seleção in qualifying for the latter stages of the U-20 equivalent. Now the Celtic striker wants to prove that the potential displayed in those youth showpieces has blossomed into a talent worthy of gracing the biggest stage of all.

He said: "I was very envious watching the last World Cup but also very proud, because what the lads did in Germany really put Australia on the football map. I've seen how much more respect we've been given since then and, back home, it's raised interest to a level that just's unbelievable compared to a few years back.

"Now we need to keep that momentum going by getting to South Africa and hopefully going even further than in 2006. Personally, the tournament should be a perfect time for me age-wise and if things keep on going as well for me at Celtic as they have so far, I'd be hopeful of doing well there. For me, that's what it's all about. It's not enough just to be in South Africa - I want to be making a big impact."