This is where it gets difficult. Unimaginably difficult. Only twice in 112 years have the Lions clinched a series against a major southern hemisphere power by prevailing in the final Test, and as the first example was back in the 19th century, it is safe to say that Warren Gatland's tourists will be flying in the face of history when they meet the Wallabies in Sydney this weekend. All things considered, it might be easier for a unicyclist to win the Tour de France.
The good news? On both said occasions, they pulled the last-Test trick here in Australia, most recently in 1989, when Finlay Calder and his fighting pack of lawyers and police officers stared down the home side and took the spoils by a single point, aided and abetted by an infamous piece of cock-uppery from the great David Campese, of all people on God's rugby earth. Can it conceivably happen this time, now that the Wallabies have their tails up and the Lions are suffering the body-count from hell? It is a big ask, for sure.
Optimists will point to the fact that Australia's most creative backs, James O'Connor and his fellow "bad-boy amigo" Kurtley Beale, are a long way short of their best – that their combined failure to shape a game to the liking of the astonishing new wing sensation Israel Folau gives the Lions, resilient as they are, a degree of hope. Yet pessimists will insist, quite rightly, that if the O'Connor-Beale axis at 10 and 15 had worked more smoothly at the weekend, the Wallabies might have won by plenty, rather than by a measly, miserable point.
That the Lions went so close to closing out a series for the first time in 16 years was down to two things, and two things only: the profligacy of the Australian midfield decision-makers, and their own mighty performance in defence. As the second half of a neurotic encounter unfolded – there was nothing of the free-running extravaganza we witnessed in the Brisbane Test; just a hard, unbearably tense exercise in zero-sum rugby – images of Durban 1997 invaded the mind's eye. On that triumphant night of nights in Natal, the Lions tackled their hearts out and trusted to luck that the Springboks would mess up, which they duly did. This time, under similar circumstances, the Wallabies were almost as generous, but not quite.
Not until six minutes from time did they get it absolutely right with ball in hand, but when they did, they were lethal. Folau's long-limbed slink into the Lions' 22, Sekope Kepu's drive into the soft underbelly of the red-shirted line, Will Genia's instinctive recognition of possibilities going left, O'Connor's delayed pass, Adam Ashley-Cooper's ruthless finish, Christian Leali'ifano's supremely confident conversion… under the circumstances, it was a try worthy of its rewards.
"You have to push the envelope in order to win," the Wallaby coach, Robbie Deans, said yesterday, after a blissful night's sleep. "We'll never beat a side as able and experienced as these Lions without chancing our arm, so it's down to the decisions players make in the moment. There's a tipping point: we may have made errors early in the game but we also asked a lot at that stage, and the demands you're prepared to make of yourself can be the difference at the end. You have to keep asking, keep probing. When it came down to it, we got the job done."
As a summary of the difference between the two sides, this was just about spot-on. As Jonathan Sexton, the Lions outside-half, hinted immediately after the game, teams who set out to beat the Wallabies by playing anti-rugby – by simply squeezing and tackling and eking out tiny territorial gains and kicking penalties as and when they arise – will lose as often as they win. Far more often, probably.
"There was a lot of emotion about us, but there's a balance we need to strike between emotion and performance," said the Dubliner, who invariably presses more attacking buttons for Leinster and Ireland than he did for the Lions in this game. "There's no point being the most passionate team if you can't execute, if you can't get set-piece ball and finish your tries. At times, we were wishing the game would end rather than going after it. That's how I felt, anyway."
That the Lions had a kick to win it at the death, just like the Wallabies in Brisbane, is a matter of fact, but Leigh Halfpenny's shot was even more demanding than Beale's had been seven days previously and while the Welshman did not shank it a la Kurtley, it was just about his worst strike of the trip. In truth, the tourists were no worthier of victory here than the Australians would have been first up.
Their set-piece work was below par: Mako Vunipola's travails on the loose-head side of the front row prompted the Wallabies to scrum free-kicks and penalties as early as the 13th minute, an example of rugby through the looking glass if ever there was one. Life was not so good at the line-out either, as Geoff Parling, the England lock making the decisions in this crucial department on his first Test start as a Lion, confessed. One attacking line-out late in the game, stolen by the substitute Wallaby back-rower Liam Gill, really hurt the tourists. "It was a shit call by me," Parling lamented. "It was my responsibility, so it's hard to take."
His opposite number, the highly accomplished Wallaby captain James Horwill, had no such regrets, although he was sufficiently alarmed at the profligacy of his back division to give O'Connor and Beale a piece of his mind. "We pushed too many passes, tried to throw too many miracle balls," he complained. "We have to be better than that. We must learn to look after possession." There again, the amigos were at least trying to create something. Both wings, Folau and the impressive newcomer Joe Tomane, had their moments, which was more than could be said for Tommy Bowe and George North.
Maybe the Lions would have won but for the absences of the inside centre Jamie Roberts and the scrum-half Mike Phillips; the injuries that deprived them of two key tight-forwards in the prop Alex Corbisiero and the lock Paul O'Connell. On the other hand, might not the Wallabies have prevailed in Brisbane had they not lost three backs to the stretcher-bearers and ended up with a flanker in midfield and a scrum-half on the wing?
When someone suggested to Sexton that to win in Sydney, the Lions would have to do more than kick goals, the Irishman nodded in agreement. You could see his point. With Folau at his scariest, Genia at his most majestic and the O'Connor-Beale link likely to be better for another savagely hard hit-out, the Wallabies will almost certainly cross the whitewash. Do the tourists have it in their make-up to respond in kind? Now, there's a question.
Australia: Try Ashley-Cooper; Conversion Leali'ifano. Penalties Leali'ifano 3. British & Irish Lions: Penalties Halfpenny 5.
Australia: K Beale (Melbourne Rebels); I Folau (NSW Waratahs), A Ashley-Cooper (NSW Waratahs), C Leali'ifano (ACT Brumbies), J Tomane (ACT Brumbies); J O'Connor (Melbourne Rebels), W Genia (Queensland Reds); B Robinson (NSW Waratahs), S Moore (ACT Brumbies), B Alexander (ACT Brumbies), K Douglas (NSW Waratahs), J Horwill (Queensland Reds; capt), B Mowen (ACT Brumbies), M Hooper (NSW Waratahs), W Palu (NSW Waratahs). Replacements: R Simmons (Queensland Reds) for Douglas, 52; S Kepu (NSW Waratahs) for Alexander, 58; J Slipper (Queensland Reds) for Robinson, 60-76; L Gill (Queensland Reds) for Palu, 60; R Horne (NSW Waratahs) for Ashley-Cooper, 77.
British & Irish Lions: L Halfpenny (Cardiff Blues); T Bowe (Ulster), B O'Driscoll (Leinster), J Davies (Scarlets), G North (Scarlets); J Sexton (Leinster), B Youngs (Leicester); M Vunipola (Saracens), T Youngs (Leicester), A Jones (Ospreys), A W Jones (Ospreys), G Parling (Leicester), D Lydiate (Newport Gwent-Dragons), S Warburton (Cardiff Blues; capt), J Heaslip (Leinster). Replacements: C Murray (Munster) for B Youngs, 53; R Hibbard (Ospreys) for T Youngs, 55; D Cole (Leicester) for A Jones, 58; S O'Brien (Leinster) for Heaslip, 63; T Croft (Leicester) for Warburton, 66.
Referee C Joubert (SA).
Decision days: the other Lions series that went down to the wire
1903: South Africa
Johnny Hammond's team visited South Africa for the third time for a three-match series. After draws in the first two Tests, 10-10 in Johannesburg and 0-0 in Kimberley, the series was decided in Cape Town, where the hosts won 8-0.
1910: South Africa
The Lions' next visit to South Africa also went down to the last of three Tests. After losing the Johannesburg opener 14-10, an 8-3 victory in Port Elizabeth set up another Cape Town showdown, where the South Africans scored four tries in a 21-5 victory.
In the Lions' first Australia-only tour for 90 years, Ian McGeechan's side lost 30-12 in Sydney before levelling the series in Brisbane with a 19-12 triumph. The turnaround was completed back in Sydney, the tourists, captained by Finlay Calder, becoming the first Lions team to win a series after losing the first Test as they prevailed 19-18.
1993: New Zealand
Again coached by McGeechan, the Lions lost 20-18 in Christchurch before levelling a fortnight later with a 20-7 triumph in Wellington. A captain's performance in Auckland from Sean Fitzpatrick then led the All Blacks to a comfortable 30-13 win for the series.
The outcome of the Lions' last series in Australia was unclear until the final match – and this tour has so far taken a similar course to 12 years ago. Jason Robinson and Brian O'Driscoll tries set up a 29-13 win in the Brisbane opener but Australia, then world champions, enjoyed a 35-14 win in Melbourne. Graham Henry's side then lost 29-23 in the Sydney decider.