Sexton needs to step up and show Gatland he's man for big occasion
The two players Warren Gatland could ill afford to lose from his playing party were Billy Vunipola and Owen Farrell.
One was gone before the plane took off from London, but Taulupe Faletau has stepped in and stepped up to be one of the tour's top performers.
The other, Farrell, is a major doubt for the first Test after damaging his quad muscle yesterday. If the Lions are to succeed, Gatland needs Johnny Sexton to step into the breach a la Faletau and lead the tourists' backline.
It has been an eventful tour already for the Ireland out-half, who might have been tempted to pack his bags after the way things unfolded in the first two games on tour.
On the back of a poor performance against the Scarlets in the Guinness PRO12 semi-final, he fell off the plane face first instead of hitting the ground running, but got a reprieve due to others' misfortune and has played his way back into form.
News that Farrell would miss the clash with the Maori All Blacks tomorrow came through a couple of hours after the England fly-half had surprisingly been left out of the starting XV named in Rotorua.
He had been picked on the bench, but then he was replaced by Dan Biggar as news of his injury was released. Farrell (below) was photographed kitted out at training yesterday.
A grade one quadriceps strain was the official reason for his absence and, eight days out from the meeting with the All Blacks at Eden Park, the timing couldn't be worse.
So, whatever Gatland's plans for pairing the two out-halves together in a 10-12 axis were, they've gone out the window.
Instead, the coach combines Sexton with two men he knows well; his long-time international partner in crime Conor Murray and his one-time Leinster colleague Ben Te'o in a line-up that has the look of a Test XV about it.
"Johnny continues to need some more rugby and we're building him towards that," Gatland said at the team announcement press conference when the full extent of Farrell's issue was not in the public domain. "He was really good off the bench against the Crusaders and the combination of numbers 10 and 12 was seamless.
"He knows that his games before weren't his best, the Barbarians game and the PRO12 semi-final, he was down a bit on confidence but he's got his mojo back and we wanted to give him a start."
Alun Wyn Jones' extra minutes mean he drops out for Maro Itoje with Iain Henderson on the bench, and the Wales skipper could return; while Mako Vunipola and Jack McGrath are neck and neck for the loosehead berth.
If Sexton can guide this team to victory in Farrell's absence, then they'll have taken a big step forward.
The Maori have named a strong team that includes World Cup winner Nehe Milner-Skudder and Liam Messam, the Ioane brothers who terrorised the Lions last week in Auckland and pocket rocket Damian McKenzie.
Their back-row is ultra dynamic, and will test the combination that so impressed in Christchurch a week ago and are threatening to confine Sam Warburton to the bench next week.
Gatland was impressed by their work and liked the balance they brought.
"We recognise that loose forward trio went really well on Saturday," he said of the O'Mahony, O'Brien, Faletau axis that performed so well in Christchurch.
"The challenge for them is to repeat it. And if they do it again, we'll make what we think is the right selection for the Test match.
"Sam will come off the bench, CJ (Stander) did well coming off the bench too and has had quite a lot of rugby.
"Some others are being rested and are being kept for part of the 23 for the first Test as well, because some of them have had a lot of rugby and need recovery time.
"We're just trying to mix and match and think two steps ahead. There's a little bit of juggling going on at the moment.
"There was a nice balance between that loose-forward trio the other day. We put the Crusaders lineout under some pressure.
"One strength has been the lineout. We know Peter's exceptional there, whether in attack or defence.
"Toby's obviously very good in the air too at lineout time. We've got plenty of variation, a lot of pace in that back-row."
Murray is the centre of attention in New Zealand right now after Graham Henry labelled him the best scrum-half in the world and Steve Hansen identified his box-kicking as a key area; meaning he can expect plenty of attention.
His experience of working with Sexton should help matters as they all grow accustomed to the systems of play. With Te'o and Jon Davies, there is plenty of power in the midfield with the guile of Anthony Watson on one wing and the strength of George North on the other.
At the back, Leigh Halfpenny is a safe pair of hands who will most likely kick the goals.
Up front, the Lions' tight five have been getting it in the neck about the scrum and will want to prove a point and show referee Jaco Peyper - who referees the first Test in a week's time - what they are about.
Everyone in New Zealand is weighing in on the tourists' set-piece in what seems like a concerted campaign.
This game marks a handover from warm-up officials to the Test match trio, who will rotate through the remaining six fixtures and will represent another change of interpretation.
Defeat for the Lions would be a major setback to their ambitions.
Moving on to face the Chiefs with three defeats in five games would not be good for business, and with doubts surrounding Farrell's participation, morale could be at risk as they travel to Hamilton and on to Auckland.
Hansen is already sniping from the margins, yesterday suggesting that there will be a split in the Lions squad and predicting the arrival of reinforcements from home to bolster the numbers.
He'll only ramp it up next week if he thinks the pressure will tell on Gatland.
The Lions need a statement of intent in what is being billed in some parts as the fourth Test. With O'Mahony leading and Sexton directing them they have the necessary experience to deal with what's coming, but this tour has been tricky to date and this is no easy fixture.
British & Irish Lions: L Halfpenny; A Watson, J Davies, B Te'o, G North; J Sexton, C Murray; M Vunipola, J George, T Furlong, G Kruis, M Itoje, P O'Mahony, S O'Brien, T Faletau. Replacements: K Owens, J McGrath, K Sinckler, I Henderson, S Warburton, G Laidlaw, D Biggar, E Daly.
NZ Maori: J Lowe; N Milner-Skudder, M Proctor, C Ngatai; R Ioane; D McKenzie, T Kerr-Barlow; K Hames, A Dixon (captain), B May, J Wheeler, T Franklin, A Ioane, E Dixon, L Messam. Replacements: H Elliot, C Eves, M Renata, L Price, K Pryor, B Hall, I West, R Thompson.