"Ash put in a fantastic performance up front. He has been solid in our defence but I thought we should try him up there.
"He played with great composure and after showing that skill he'll be staying up there.
"I'm glad we kept going in the game and played with a lot of heart right to the end."
United took the lead in the 15th minute thanks to a right-footed Rudman strike in the box.
The in-form striker then doubled his side's lead 10 minutes later after beating the home side's keeper to the ball and slotting home from close range.
And Rudman calmly finished his hat-trick with an impressive solo run from 30m out, beating the last defender and drilling home from the edge of the box.
After the break Taumano neatly tucked away a Jason Walker cross in the opposition's area after 60 minutes.
Tauranga Boys' College restored some pride with 10 minutes to go after winning a free-kick on the edge of the box which resulted in the ball deflecting off the United wall and into the own goal.
The result sees United remain sixth on the table on 22 points - just a point gap between themselves and fifth-placed Melville United and three points behind third-placed Cambridge FC and Otumoetai FC in fourth.
Meanwhile, leaders Ngongotaha AFC extended their lead to six points at the top of the table with a narrow 2-1 away victory over Melville United thanks to goals from Eamon O'Donoghue and Josh O'Sullivan.
Results:
WaiBOP Premiership
Tauranga Boys' College 1st XI 1 Rotorua United 4, Melville United Prem 1 Ngongotaha AFC 2, SGS Papamoa Premiership 1 Cambridge FC Prem 1, Katikati FC Ambria Premiership 0 Otumoetai FC First Credit Union 1, Tauranga City Premiership 0 Waikato Unicol AFC Prem 5, Old Blues Prem 3 Matamata Swifts Prem 2.
WaiBOP Championship
Whakatane Town Champ 0 Ngongotaha Champ 3, Old Blues Champ Matamata Swifts Reserve (postponed), Tokoroa AFC 4 Otumoetai FC Mens Champ 1, Te Awamutu Edmond Judd Champ 3 Hamilton Wanderers Champ 1, Waikato Unicol AFC Reserves 0 Taupo AFC Champ 7, West Hamilton Champ 2 Cambridge FC Champ 1.