Twickenham - Wallaby coach Michael Cheika said he would put his longstanding friendship with Eddie Jones on hold when the new England boss arrives in Australia for a three-Test series in June.
The pair, who first knew each other as forwards with Sydney club side Randwick, now find themselves in charge of two of rugby's elite tier one nations.
Friday saw the 55-year-old Jones given the task of reviving England's fortunes, after the 2015 hosts' first-round exit at the World Cup, when he was installed as coach in succession to Stuart Lancaster on a four-year contract.
Jones, Australia's coach when they lost the 2003 World Cup final to England in Sydney, now has the task of putting his own stamp on the Red Rose brigade ahead of their Six Nations opener away to Scotland at Murrayfield on February 6.
But the end of the European season is also set to see Jones lead England in Australia, with the reigning southern hemisphere Rugby Championship title-holders underlining their credentials in a gallant 34-17 World Cup final defeat by New Zealand at Twickenham last month.
"Good luck to Eddie. I want him to do well as a mate...but not when England come over!," Cheika said Saturday.
"I'm looking forward to the opportunity when we go up against each other. Just for the fact that I'm really proud that we're both from Australia and come from the same club, Randwick, and will be doing battle in a different arena.
"It's going to be a bit weird but there's no such thing as friends when the game's on."
Cheika, back at Twickenham in the temporary role of coaching the Barbarians in a 49-31 defeat by Argentina, added: "Eddie has some very important encounters in the Six Nations before then but I'm sure there will be a bit of banter when England are due to come over to our place.
"That's all good fun because both of us enjoy that kind of thing. That's part of our relationship I suppose.
"I played with Eddie and I'm not much younger than him," said the 48-year-old Cheika, Randwick's No 8 when Jones was the Galloping Greens' hooker.
Cheika may have enjoyed World Cup semi-final success over Argentina, but the Pumas turned the tables on Saturday as they scored seven tries to his Barbarians team's five in a non-cap international that helped celebrate the invitational side's 125th anniversary.
It was an emotional day which saw a minute's silence for the victims of the Paris attacks of November 13 as well as in memory of New Zealand great Jonah Lomu, a former Barbarian, whose sudden death at the age of 40 on Wednesday stunned the world of rugby.
The Pumas showed their respect by wearing black jerseys with the No 11 on during the warm-up in recognition of the shirt worn by the late All Blacks left wing.
Barbarians left wing Nemani Nadolo went a step further, with the giant Fijian, who at 6ft 4in and nearly 20 stone has a physique to rival that of Lomu, wearing a white No 11 on the back of his shirt rather than having his number printed in traditional Baa Baas black.
Nadolo also scored a try reminiscent of Lomu when he charged past opponents on his way to the line.
But the match belonged to Argentina, who carried on from where they left off at the World Cup with an attacking game that is set to be a part of next year's edition of Super Rugby as well with the creation of a new franchise in Buenos Aires.
"It won't be long before they are top of the Super Rugby tree," said Cheika. "They (Argentina) have a new generation of fine players and have come a long way since joining the Rugby Championship."
Pumas coach Daniel Hourcade, smiling again after Argentina's 29-15 World Cup loss to Australia left him in tears, said: "I am proud of my team and their attitude. They took this game very seriously and it was a fine performance."