The East succumbed 24-0 to a side that looks primed to lift the silverware on Wednesday.
The better of the two Rotorua sides have secured a four-try bonus point in each of their matches so far, and will start as favourites at 1.30pm today against fourth seeds Te Puke.
Opotiki will play Rangitaiki at Blake Park at 12.15pm in a battle between the fifth and eighth ranked teams, with sixth-placed Whakatane to meet seventh seeds Rotorua Gold at 11am.
The ninth and 10th ranked sides - Apanui and Galatea - have a bye but will in action against each other on finals day on Wednesday.
Day four results, Monday, July 15
Galatea 13 Opotiki 19
Te Puke 93 Rangitaiki 0
Apanui 0 Whakatane 38
Tauranga East 0 Rotorua Maroon 24
Rotorua Gold 3 Tauranga West 97
Tai Mitchell semifinal draw for Tuesday at Blake Park
11am - Whakatane (6) v Rotorua Gold (7), Blake 2
11am - Tauranga East (3) v Tauranga West (2), Blake 1
12.15pm - Opotiki (5) v Rangitaiki (8), Blake 2
1.30pm - Rotorua Maroon (1) v Te Puke (4), Blake 1