SYDNEY (Reuters) - To beat the All Blacks once on home soil has always been a Herculean task. To do it twice, as the British and Irish Lions must to win the upcoming test series, is rugby's Mission Almost Impossible.
The pace and physicality with which the All Blacks have played rugby over the last eight years has taken their dominance of the game to another level and a strong argument could be made for rating them the best team of all time.
Still, sport has a habit of throwing up surprises and Warren Gatland has brought together the cream of four proud rugby nations in a party he feels can achieve what only one previous Lions squad has done in more than a century of trying.
Notwithstanding the inevitable injuries, Gatland will already have his matchday 23 and the tactics he feels can unseat the world champions sketched out in his head.
He knows it is a challenge of an altogether higher order to that of 2013, when he brought "Warrenball" and his "slabs of red meat" to Australia and won the series 2-1.
He did it by sending big ball carriers crashing over the gainline, turning the screw at the scrum and relying on Leigh Halfpenny's almost unerring accuracy from the tee to punish Wallaby errors.
The kicking will be just as important this year but Gatland is a Kiwi born and raised and he knows it will not be easy to overpower the All Blacks however much British and Irish beef he can throw at them.
Ireland's first win over the All Blacks in 111 years, a stunning 40-29 triumph in Chicago last November, showed that it is possible to outwit the world champions if you bring something different and hold your nerve.
The Irish victory at Soldier Field also illustrated another factor that Gatland has undoubtedly taken on board - to beat the All Blacks you need to score tries.
Only four teams have beaten New Zealand since they won the first of their back-to-back World Cups in 2011, and all have had to score at least three tries to do it.
Whether Gatland can piece together a backline that can carve out enough try-scoring opportunities remains to be seen but it will be in his selection of the centres that he will show his hand most clearly.
If he perms a pair of bruisers from Jonathan Davies, Robbie Henshaw and Ben Te'o, it will signal that "Warrenball" is undergoing evolutionary rather than revolutionary change.
If Owen Farrell is included as a second playmaker outside Jonny Sexton, or the fleet-footed Jonathan Joseph is in the number 13 shirt, we could be in for that all-important 'something different'.
After forging their combinations in the fire of the tour games, Gatland and his coaching team then have to worry about what is coming the other way.
New Zealand have quality throughout - from tight forwards who get around the park like flankers and have the handling skills of three-quarters to outside backs who make kicking away possession a risk bordering on the suicidal.
You must aim to play error-free rugby as New Zealand teams are never more dangerous than from turnover ball, they never consolidate but immediately start probing the gaps opened up by the unexpected change in possession.
Gatland, of course, has a few handy operators in his party too and he put the emphasis in his squad selection on experience and big-match temperament.
The undoubted strength of the pack should ensure parity at the very least at the set piece and breakdown as well as a steely defence, enabling the tourists to keep the game as structured as possible.
The key to the series will be whether they can then put the All Blacks under pressure for sustained periods, particularly in the opening test when the hosts are traditionally at their most vulnerable.
One of the downsides to winning, and dominating, almost every match is that you are never quite sure how your players are going to react when they do fall behind.
Scrape a result at Eden Park on June 24 and not only will the old sporting magic of momentum come into play, but it might just reawaken the national nervousness that prevented the All Blacks from winning the World Cup between 1987 and 2011.
Editing by Peter Rutherford