With the three-match series against world champions South Africa now just a week away, the focus is beginning to turn to the formation of the Test team for the first international in Durban on June 20.
McGeechan has repeatedly made it clear to both his players and the press that every single Lion will be given ample opportunity to impress, but time is now running out for those Lions yet to cement their place in his first choice XV.
The Lions head coach has named an entirely different starting XV from Wednesday night's win over the Sharks as he continues with his aim of giving each player two starts prior to selection for the opening Test match.
Although McGeechan has publicly stated that he and his fellow coaches will not be selecting the Test 22 until after Tuesday's clash with the Southern Kings, many of the hopefuls taking the field at Newlands will know that this is their final chance to press their Test claims.
Such a realisation will hopefully bring out the best in Britain and Ireland's elite as they look to make the most of what could be a once in a lifetime opportunity.
Saturday's side features a mixture of youth and experience, with England's Phil Vickery captaining the side from the front row, while the likes of Keith Earls and Ugo Monye are named out wide.
Two favourites for Test selection prior to departure for South Africa return to the Lions side following injury enforced absences, with Martyn Williams and Riki Flutey looking for big performances to dislodge David Wallace and Jamie Roberts from the openside flanker and inside centre spots respectively.
A knee injury has limited Flutey to just two substitute appearances against the Royal XV and the Sharks and a problematic shoulder has seen Lions veteran Williams sidelined since the opening tour fixture on May 30.
Williams' Cardiff Blues and Wales colleague Andy Powell is likely to need a big performance following Jamie Heaslip's try-scoring 80 minutes against the Sharks, while Joe Worsley will be glad to be back on the blindside flank having started at openside against the Cheetahs a week ago.
Elsewhere in the pack, Donncha O'Callaghan will be hopeful of joining his Munster team-mate Paul O'Connell in the second row against the Springboks; Matthew Rees will be keen to give a timely reminder of his attributes following Lee Mears' impressive mid-week display; and Nathan Hines and Andrew Sheridan will be looking to show that their power and physicality will be needed at the ABSA Stadium in Durban.
As for the backs, Tommy Bowe and Monye return to wings following 10 days without a game and both will be looking to start where they left off in their previous outing against the Golden Lions. Ospreys and Ireland star Bowe was one of the stand out performers in that fixture, scoring once and playing a large part in a number of other scores, while England international Monye crossed for a brace of well-taken tries on his debut in Lions colours.
They are joined in the back three by Rob Kearney, who will have watched Lee Byrne continue to shine in the No15 shirt on Wednesday and will therefore be even more determined to put in the kind of performance that makes the coaching staff sit up and take notice.
Flutey is joined in the centre by Earls, now the youngest man in the Lions playing party following the reoccurrence of Leigh Halfpenny's quad injury.
Stephen Jones of the Scarlets links up with Leicester Harry Ellis at halfback, with James Hook and Mike Blair hoping to be given a chance of game time from the replacements bench.
While the players chosen to represent the Lions this weekend know they have everything to play for, those selected for Western Province will argue that Saturday's match carries just as much importance for the home side.
Whereas the Lions tour once every four years, meaning a number of the current squad will have already been part of a previous tour or will feature in a future Lions adventure, all bar three of the Western Province XV will more than likely be making their only appearance against the world's most-famous touring team.
Only centre Morgan Newman, hooker Tiaan Liebenberg and openside Duane Vermeulen stand a chance of facing the Lions again on the current tour, with none of the squad likely to be involved the next time the Lions arrive in the Republic in 2021.
Newman was a surprise inclusion in Peter de Villiers' 28-man Springbok squad for the Castle Series, while Liebenberg and Vermeulen have been chosen as Emerging Springboks for the clash against the Lions on June 23.
The trio provide three of the biggest threats to the Lions' superiority at Newlands and Newman in particular will be anxious to persuade de Villiers that his inexperience at the highest level will not be a liability against Britain and Ireland's elite. The 23-year-old only made his Super 14 debut last year but has been catapulted into the Springbok reckoning where he joins the likes of Jean de Villiers, Adi Jacobs and Jacques Fourie in pushing for a Test spot in the centres.
While Newman, Liebenberg and Vermeulen have yet to win a South African cap (Newman featured in the non-cap fixture against a Nambibian XV last month), wings Tonderai Chavhanga and Gcobani Bobo, inside centre Peter Grant and No8 Luke Watson have already represented the Boks in full internationals.
Chavhanga made his international debut against Uruguay in 2005 and has gone on to win four Springbok caps, while both Bobo and Grant have made five appearances for his country since 2003 and 2007 respectively.
While Grant has perhaps the most unfortunate of that trio to miss out on Springbok selection for the series against the Lions, it is Watson who was the most high-profile Western Province omission from de Villiers' chosen 28.
The back row star has been in stunning form for the Stormers in 2009 but was unable to oust Pierre Spies and Ryan Kankowski from the national squad after he was considered as a No8, as opposed to his traditional position of flanker.
Watson, whose father 'Cheeky' was a prominent figure in the anti-apartheid regime, has long been one of the most controversial figures in South African rugby. Watson was recently the subject of much media attention following a speech in which he mentioned 'vomiting' on the Springbok jersey. Now he will be hoping to grab the headlines for his performance on the field as Western Province look for their fourth win over the Lions in 16 attempts.
The last of those victories came in 1938 but five of the Lions' last six wins have come by nine points or less. In fact, the Lions have only ever beaten Western Province by 10 points or more two occasions: once in 1896 and the other on their last tour of South Africa in 1997.