Nanai and Thompson were joined in the semifinals by Wayne Tautau and Tony Cleaver.
Thompson beat Tautau and Nanai eliminated Cleaver.
Six players contested the C Grade crown — Larry Robinson, Dave Middlemiss, Athol Hjorring, Mary Kerekere, Te Rina Hawkins and Busby Akuhata.
From the three sections, Akuhata, Robinson, Middlemiss and Hawkins advanced to the semifinals.
Akuhata beat Robinson and Middlemiss defeated Hawkins.
Akuhata beat Middlemiss in the final.
Ten players entered the B Grade championship last month, with Raggett defeating Nathan Coombs in the final.
Raggett knocked out Tiny Thompson in one semifinal, while Coombs beat Middlemiss in the other.