David Tua tries to duck a right hook from Alexander Ustinov during their bout in Hamilton.

A ring girl holds up the round two card during the Nikolas Charalampous-Rico Chong Nee bout.

The referee raises Alexander Ustinov's arm as David Tua looks confused at the result.

David Tua looks on disappointedly after his unanimous points decision loss.

David Tua cops a right from Alexander Ustinov flush on the chin.

David Tua confirmed his professional boxing career was over after his unanimous points defeat to Belarusian Alexander Ustinov in Hamilton tonight.

"I got into very good shape believing I could win this fight ... I tried my best but it wasn't enough," Tua said.

"I think the fire isn't there, it's time to think about something else.

"That's it for David Tua. I thank the people of New Zealand, I thank the people of the south Pacific ... David Tua has left the building."

Hope can blind reality.

That, perhaps, best sums up what should be the final chapter in David Tua's flat-lining career after losing a unanimous points' decision and any shot at a second world title challenge to Alexander Ustinov in Hamilton tonight.

They say a last thing a heavyweight loses is his power.

Either Ustinov can withstand more power punches than any other opponent Tua has fought, or the aforementioned is, indeed, the harsh truth for Tua.

This was everything or nothing for the favourite Samoan-Kiwi boxer. No matter the post-fight spin, this was his last, genuine chance. Retirement should now follow.

Before the opening bell the noise was deafening. It was electric, but, ultimately, that's where excitement ceased for locals.

The stare of hunger and intense motivation was obvious in Tua's eyes. After a$50,000 training camp - a convenient calf injury and subsequent postponement - Tua dropped 50kg in a remarkable transformation.

With K2 Promotions manager Alexander Krassyuk in attendance, Tua couldn't have asked for a better scene to revive his career.

Tua had done everything he could for his first fight in two years. This was supposed to be his time. Ahead of his 41st birthday on Thursday his final, brave comeback.

Ustinov - ranked 8th, 12th and 15th - by the respective IBF, WBA and WBO organisations - had other ideas. His persistent left jab proved menacing.

At times the 2.03m giant Belarusian giant was careful to keep his distance and avoid Tua's unrivalled left hook, but he was also not afraid to mix it with him in close.

Giving up 25kg and 25cm in reach, Tua was always going to find it difficult to get inside his towering opponent. His notorious problems challenging taller boxers were again exposed.

A point's victory was never serious contemplated. Tua had one option. That was to deliver his first knockout blow in four years. It never looked likely.

Connecting from the outside couldn't produce enough power. Tua collectedUstinov with a series of one-off left hooks but all failed to rattle the visitor. He kept coming back for more. His big tree-trunk legs never wobbled.

As the fight wore on, Tua appeared deflated in the corner. Ustinov seemed to grow taller, certainly grow in confidence.

No-one can suggest Tua didn't give every last ounce of passion. He simply wasn't good enough.

And so his tale of heartbreak; a story of lost millions, a messy divorce and wasted talent through inactivity comes to a near conclusion.

After an at times stunning 21-year professional career, which featured knockouts of four world champions John Ruiz, Oleg Maskaev, Hasim Rahman, Michael Moore, Tua deserves more than living out of his Onehunga gym and driving a black mini.

He may now be forced to turn his attention to a hopeful political career.