The other games are the Premier grade Maddison Trophy semifinals, at 1.30pm between Taradale and Napier Old Boys Marist, and at 3.30pm between Napier Technical and Hastings Rugby and Sports.
The other Reserve grade semifinal, between Napier side Pirates and Old Boys Marist, is at Tremain Field in Napier's Park Island reserve, and other semifinals through the grades will be at the Otane Domain, White Domain at Porangahau, and Dannevirke's Rugby Park.
Despite significant scrutiny, the HBRU came through with flying colours in the way it managed last weekend's club matches, with a rearrangement of venues at short notice including matches at Tremain Field on both Saturday and Sunday.
Union club rugby ambassador Gary Macdonald said clubs have been advised individually of plans to admit fans at McLean Park to be seated in "bubbles" of up to 100, which could be possible in a large seated stadium.
Clubs are allocated separate gate assembly points and when gathered groups will be escorted to a selected area of the Harris Stand, seated 2 metres apart and with each bubble separated.
There also rules around departure after each game, and for the players the use of the changing rooms, with six available at the park.
Union CEO Jay Campbell said it was great that a club like Maraenui is able to play in Hawke's Bay's major sports stadium. It hasn't played Premier club rugby since relegation in 2004 and hasn't played at the park since losing a Division 2 final there against Dannevirke club Aotea a year later.
"McLean Park is the jewel in the Crown of rugby, and sport generally, in Hawke's Bay," he said. "It's excellent for Maraenui to have the opportunity, and for that thanks go to the Napier City Council for allowing all three games to go ahead. We also congratulate the clubs of Hawke's Bay for their flexibility, and the way they have picked up the challenge in ensuring community rugby was able to be played this season."
It is thought unlikely that anything other than the Maddison Trophy final and the Colts grade final will be able to be played at the park the following week, the last before the first Hawke's Bay Magpies home Mitre 10 Cup match, against Canterbury on September 26.
Current Maraenui coach Mark Huata played in the club's last game at McLean Park, and in one other, a Premier victory over Clive, and is working to make sure the team isn't overawed by the significance of the moment.
"Most of these players may never get the chance to play on McLean Park again," he said at training on Thursday night.
He then suggests it would have been nice if the union had offered the chance of promotion to Premier, especially with the club celebrating its 40th anniversary next year, needing the opportunity to retain players and grow numbers, after a season in which work commitments, including forestry, kept numbers to a near minimum. Only once, in the opening game, did Maraenui field a full squad with a "full bench".
While promotion is regularly on the line, it was not at stake in 2007, when Maraenui went unbeaten to win the Division 2 competition, nor last year when they played Otane another Division 2 final, won by Otane.
It is also not on the line this year, in which Maraenui were put into the Reserve grade to avoid what would have been crippling costs of playing in a Division 2 competition otherwise comprising only teams from CHB and Dannevirke.
Team captain and lock Stephen Te Patu said that not only is it an opportunity for the players but also "an incentive for all the other younger ones, to know that we can do it…so can they".
"Play hard, hit hard, nui hard," he says reeling off the war-cry of a club all regard as a family club.
Club stalwart Gene Porter didn't get on to the park as a player, but would have "loved to" have had the opportunity, and will be here to take in the opportunity of this generation.
As for overcoming the restrictions on crowd numbers and possibly being left at the gate, he advised: "Show up early, or put some boots on."