With WBO and WBC belts on the line, Usyk and Briedis put on a startling display for the fans at the Riga Arena in what turned out to be a closely-fought battle.
The early stages went the way of Briedis who began the brighter and seemed to be frustrating Usyk at times by getting his punches off first.
Usyk suffered a cut in the third round from an accidental headbutt but caused damage himself in the fifth when bloodying Briedis to the nose.
Despite coming on strong in the sixth, Briedis seemed affected in his breathing from then on and showed slight signs of fatigue as Usyk took over.
Racking up five rounds in a row on the WBN Scorecard, albeit all of which were still close and competitive, it was Usyk who was beginning to pull away.
The Ukrainian was relentless in his attacks and constant walking forward whilst Briedis landed telling punches of his own when the opportunities presented themselves.
In the end, Briedis proved he fully deserved to be the WBC title holder and be sharing such a big stage with Usyk and has warranted claims for a rematch once the World Boxing Super Series is concluded.
But it’s Usyk who advances to the final in Jeddah this coming May as two judges carded in his favour 115-113, with another seeing it a draw.
Adding the WBC version to his WBO crown, Usyk marches on to the possibility of holding all four straps at one time before then heading up for a run in the heavyweight ranks.
On the undercard, a controversial scoring debate marred the end of the co-feature as Micki Nielsen defeated Ricards Bolotniks via split verdict.
It seemed as though Bolotniks may have done enough down the stretch to take the win, although a victory was overruled by two judges who carded 77-75 in favour of Nielsen.
The Dane is now 24-1, whilst Bolotniks drops to 10-4-1 following the reverse.
Filip Hrgovic showed why he began as a big pre-fight favourite by stopping Tom Little in four rounds. A crushing right hand did the damage and Hrgovic followed it up to force the referee to step in.
The big-punching Croatian heavyweight made it three knockouts in a row since entering the paid ranks and moves on to tougher tests to come in the future.
Also at heavyweight, Otto Wallin can now boast a 19-0 C.V. following a knockout win over Srdan Govedarica. The 27 year-old Swede had too much power for the Bosnian and ended the contest in the third round.
Prior to the two main contests, light heavyweight Yoann Kongolo eased past Andrejs Pokumeiko with a comprehensive ten round decision triumph.
Cards of 98-89, 98-90 and 98-91 told the story as Kongolo, 30, took his record to 11-0 in seeing his KO percentage drop to 36%.
Undefeated cruiserweight Mikael Lawal successfully made it to 5-0 with a six-round points win over Istvan Orsos in the early going, whilst Araik Marutjan also won his four-rounder against Richard Hegyi over the distance at middleweight.
Another six-round affair saw light heavyweight Jevgenijs Aleksejevs carded a split decision win over Maurice Possiti to score an eighth pro triumph.
Phil Jay is Editor of World Boxing News. Follow on Twitter @PhilDJay