To win they need to meet the target that Andy Goodway set them before the series, and improve as much between the second and third Tests as they did between the first and second. It is, as the Australians would say, a big ask. It is that way because those Australians will be unrecognisably better this week.
For confirmation of that, Goodway can consult his own memories of playing against them for Great Britain. He then needs look no further than his assistant for this series, Shaun McRae, who used to do the same job for his native Australia.
"It's easier to prepare when you've been beaten - I've always thought that as a coach," McRae says. "That has certainly applied to Australia. I was never involved with an Australian side that was beaten twice in a row."
That is the measure of the British task at Elland Road. They have to counteract what has become almost a reflex response from Australian teams of the past 20 years. They are never more dangerous than after one of their rare defeats.
Even though they have lost Brett Mullins from the side originally selected, they will be helped tomorrow by the return of one of their finest players of recent years. Bradley Clyde plays his first match of the series after recovering from a calf injury and the calm and class that he brings to the second row should dovetail perfectly with the fire and fury of Gorden Tallis. Clyde's return is bad news for Britain.
For the reputation of the Australian coach, John Lang, this match is truly a case of make or break. The Australian Super League method of choosing their coach by league position means that he is already going to be replaced next season by Brisbane's Wayne Bennett; he will hardly want to bow out as the man who lost a series to the Poms.
Lang has tried to clear his mind of all excess baggage this week and treat this game in isolation. But he watched Anglo-Australian clashes from his boyhood and is too immersed in their tradition to lose sight of the potential historic significance of this one.
The knives are already sharpened back home. John Lang? Nice bloke, good coach - but not a dominating enough personality to take Australia overseas, they are saying.
Conversely, while none of his players is being publicly critical over here, grumbles are echoing back from Australia that some, brought up on the social whirl of a Bob Fulton-coached tour, have found this trip regimented and boring.
Goodway, meanwhile, can hardly avoid being hailed as a genius if Britain win. He will be honest enough to remember that this is not a full Australian side, but few will want to devalue the achievement.
It will have been forged in failure by a group of players with memories going back to their humiliations in New Zealand last year, sick of losing and now with a new confidence in themselves.
But, for all their excellence at Old Trafford, they have much to do - individually and collectively - if they are to win a series for the first time since 1970 and the first time in Britain since 1959.
For a start, they have to answer these questions in the affirmative. Can Paul Atcheson play with the same assurance at full-back? Can they possibly keep Laurie Daley as quiet again? And can they again walk that fine line between aggression and indiscipline?
If they can answer these and all the other questions at around 3.30 tomorrow, then they will have done astonishingly well. After 27 years, though, the nagging suspicion is that it still might not be quite enough.
GREAT BRITAIN: Atcheson (St Helens); Robinson, Radlinksi (both Wigan), Newlove, Hunte (both St Helens); Farrell (Wigan, capt), Goulding (St Helens); McDermott, Lowes (both Bradford), Broadbent (Sheffield), Joynt (St Helens), Morley (Leeds), Sculthorpe (Warrington). Substitutes: Long (St Helens), Haughton (Wigan), McNamara (Bradford), Forshaw (Bradford).
AUSTRALIA: Lockyer (Brisbane); Nagas (Canberra), Girdler (Penrith), Ettingshausen (Cronulla), Sailor (Brisbane); Daley (Canberra, capt), Gower (Penrith); Stevens (Cronulla), Walters (N Queensland), Thorn, Tallis (both Brisbane), Clyde (Canberra), Smith (Brisbane). Substitutes: Adamson (Penrith), Kearns (Perth), Kimmorley (Hunter), Richardson (Cronulla).
Referee: P Houston (New Zealand).Reuse content