"I thought last week was going to be my final game, but I'm quite rapt to be asked to take on the role of coach," he said.
"It is a good opportunity for those guys who are on the verge of making the Stallions to put their hands up."
He said most of the players in the selection side were going up against their old teammates, who they played with in local club competitions this year.
"It is a mate against mate match in a sense," he said.
"I just hope we can give [the Stallions] a competitive run."
Unuwai said he went and watched WaiCoa Bay play last weekend and was impressed with the standard of football.
WaiCoa Bay Stallions: 1. Hamiora Mihaka, 2. Te Toiroa Tahuriorangi, 3. John Koko, 4. Marrin Haggie, 5. Te Miri Rangi, 6. Aaron Jolley, 7. Hayden Karena (c), 8. Jeremy Siulepa, 9. Raureti Grace, 10. Fetaiamauso Tauiliili-Pelesasa, 11. Pirikawana Taiatini, 12. Phillip Rameka, 13. Willy Rutene. Reserves: 14. Dallas Kutia, 15. Renata Leilua, 16. Tarquin Court, 17. Carlos Kohu-Martin.
Upper Central Zone XIII: 1. Lance Rolleston (Coastline), 2. Nathan Miller (Gisborne), 3. Namu Puru (Waikato), 4. Seta Nalewakalou (Bay of Plenty), 5. Maehe Roberts (Waikato), 6. Liam Pendergast (Waikato), 7. Freedom Carson (Bay of Plenty), 8. Peter Rameka (Waikato), 9. Jason Watkins (Waikato), 10. Jason Pihema (Bay of Plenty), 11. Mac Carson (Bay of Plenty), 12. Tiniwaata Dixon-Murray (Waikato), 13. Tane Leef (Coastline). Reserves: 14. Johnson Peri (Bay of Plenty), 15. Shaun Plant (Bay of Plenty), 16. Charles Nepia (Coastline), 17. Toafitu Sili (Waikato), 18. Skay Rangi (Bay of Plenty), 19. Haoro Hond-Goffe (Gisborne).