Talivaa stood in the dock in Napier District Court dressed smartly in a black pinstripe suit and a maroon tie.
Talivaa handed Judge Geoff Rea a letter of support written by a primary sponsor of the Flaxmere fighting club.
But the judge reiterated the seriousness of the offending.
The budding boxer began a sexual relationship with the complainant in 2014, when she was 14 and he was 23.
The police became involved on December 17, 2014, two days after the complainant turned 15.
The complainant's mother had gone to police and expressed her concern.
She had already made her concerns known to Talivaa and his family.
Talivaa denied the sexual relationship to police and said he thought she was 18 years old at the time.
Police told him of her age and warned him of the consequences if their sexual relationship continued.
In July the year after, police were made aware that the couple were still together. The relationship has since ended.
Judge Rea said the defendant could not say he had no idea about her young age because police had told him. "The situation here is quite unusual. He simply denied what was obvious to everybody.
"On top of that, the defendant offended in the way that he did in full knowledge that he was breaking the law having been told by police."
Philip told the judge: "A conviction of this type renders a real problem for him."
Judge Rea said the seriousness of the offending was "heavy" and he convicted Talivaa.
"It thoroughly warrants a conviction."
He said the conviction recognised Talivaa's "arrogance in continuing on despite being warned by police and the complainant's family".
He said the charge was "amplified" by Talivaa's previous convictions, mostly for drink driving, but also for more serious offences of assault and assault with intent to injure.
The charge of sexual connection with a young person carries a maximum penalty of 10 years' imprisonment.
Talivaa was remanded on bail for sentencing next month.