The brawl, which erupted in a small upstairs bar on Karangahape Rd and spilled out on to the street in the early hours of December 30, 2012, left Mr Matoka with concussion and blood pouring from an artery.
Desi Lounge was packed while the brothers celebrated their sister's birthday and Mr Matoka and Mr Leota, both Samoan, walked in.
Mr Matoka said in evidence he had downed almost a litre of gin earlier, but he and Mr Leota were adamant they did not start the mass brawl.
They said they heard raised voices in a language they assumed was Tongan and punches started flying almost without warning.
But George Moala's girlfriend of five years, Vava Fosita, said she was hit by one of the complainants, which led to her partner trying to protect her.
Judge Rob Ronayne remanded Moala on bail and told his lawyer any application for home detention should be lodged by April 17 in time for his sentencing.
He commended Moala's family and friends, occupying two rows at the rear of the court, for hearing the verdict in dignified silence.
"I thank you for the dignity you have shown — it can't have been easy to hear that verdict."
Neither Moala nor his lawyer, Paul Wicks, QC, would comment as they walked from the court on how the guilty verdict may affect his career with the Blues, which he joined in 2012 after impressive showings for the Auckland NPC team.
A young man in a group enjoying Friday drinks on a balcony opposite the court called down to journalists pursuing Moala: "Leave him alone, he's a rugby legend."
Blues spokesman Ian Hepenstall said the franchise would not comment on his future until after sentencing.
But he confirmed the player had "not been involved with the team" during the trial.
Moala is described on the Blues website as "a weapon on attack with his considerable athleticism and physicality".
Judge Ronayne told the jury to ignore any idea of "status" they may attribute to either defendant.
Crown prosecutor Josh Shaw said the brawl was a result of "cultural tension".
But that proposition was roundly rejected by Mr Wicks and Mina Wharepouri for Suia Moala.
"The Crown would have you believe the two men walked into the smoking area, announced they were Samoan and copped a hiding for that reason alone," Mr Wharepouri said.
"How realistic is that?"
The defence's witnesses said Mr Leota was challenging people to a "one-out" fight.
But nobody could give a coherent blow-by-blow account because of the large numbers of people involved as chairs and bottles flew across the bar.
George Moala is not the only Blues player in legal hot water.
Fullback and winger Tevita Li, 19, pleaded guilty to drink-driving in May but is still playing for the team after being stood down for one game.
He applied for a discharge without conviction after being caught with a reading of 45mg of alcohol per 100ml of blood.
Although the adult limit is 50mg after being reduced from 80mg in December, the limit for drivers aged under 20 is zero.
Moala's career
• Played for the Tamaki and Grammar Carlton clubs, Tonga's under-20s side and the Auckland NPC team in 2011 before joining the Blues in early 2012.
• Provincial caps — 33
• Provincial points scored — 85
• Blues caps — 28
• Blues points scored — 50 (including from 10 tries)