Darrelle Valsaint Jr. became the first fighter representing Haiti in the Olympics to the quarterfinal round. The moment came courtesy of a hard-fought split decision win over David Tshama (Congo).

One judge had the bout 29-28 in favor of Tshama, while the remaining four judges all ruled (30-27, 29-28, 29-28, 29-28) in favor of Valsaint Jr. 

Next up for Valsaint Jr. is number-two seed Gleb Bakshi (ROC), who managed a hard fought split decision win over USA's Troy Isley. Fully story of that fight can be found here: https://www.boxingscene.com/troy-isley-suffers-heartbreaking-loss-gleb-bakshi-middleweight-round-16--159470

Hosting nation Japan enjoyed success early in the Olympics but has slowly been brought back to reality as the Games have progressed. A reminder of this was found in the Round of 16 middleweight battle that saw number-one seed Oleksandr Khyzhniak (Ukraine) remind the world why he is heavily favored to win Gold.

Khyzhniak stormed into the quarterfinal round following a three-round wipeout of Yuito Moriwaki (Japan). The Ukrainian middleweight swept every round, winning by scores of 30-27, 30-27, 30-27, 30-26 and 30-26.

Moriwaki advanced this far following a split decision win over Shahin Mousavi (Iran) on Monday. He was no match for Khyzhniak, who used sheer strength to overwhelm his unseeded foe to storm into the quarterfinal round.

Khyzhniak will next face Euri Cedeno (Dominican Republic), who leaped over the top rope for his bout with Francisco Veron (Argentina) and left with a quarterfinal berth in a split decision win over Francisco Veron (Argentina). 

Scores were 30-27 and 29-28 for Veron, overruled by 29-28, 29-28 and 29-27 cards in favor of Cedeno in a dirty fight that saw both boxers frequently warned for hitting on the break, clinching and punching after the bell. 

Abilkhan Amankul (Kazakhstan) rallied from an opening round deficit to claim a well-earned decision win over Fanat Kakhramonov (Uzbekistan). Amankul won by scores of 29-28, 29-28, 29-28, 29-28, 29-26.

The fight took a dramatic turn when Amankul—an aggressive southpaw—connected with a right hook and straight left to snap back the head of Kakhramanov. The sequence forced a standing eight count, with Amankul remaining on the offensive for the remainder of the bout to earn the win.

Hebert Conceicao Sousa (Brazil) survived a late surge by Tuohetaerbieke Tanglatihan (China) to advance to the next round via split decision. Sousa—the tournament's number-three seed—won by scores of 30-27, 29-28 and 29-28 to overrule scores of 29-28 and 29-28 in favor of Tanglatihan. 

Amankul and Sousa will now meet in the quarterfinal round.

Arman Darchinyan (Armenia) rode a late round knockdown all the way to the finish line in a well-earned unanimous decision win over Andrej Csemez (Slovakia). Scores were 30-26, 29-27, 29-27, 29-27 and 29-26 in favor of Darchinyan, who remained poised after falling behind as he pulled off the victory.

Darchinyan is the nephew of the great Vic Darchinyan, a former two-division champ and one of the sport's best at his peak. The younger Darchinyan—who is 1-0 as a pro—has the chance to make his own name in Tokyo, as he is now one win away from a medal.

The win sets up a matchup of pro boxers meeting on the Olympic stage, as Philippines' Eumir Marcial advanced following a 1st round stoppage of Younes Nemouchi (Algeria). 

Marcial—the number four seed and who fights under Manny Pacquiao's MP Promotions banner as a pro—scored a knockdown less than a minute into the bout, with Nemouchi's night getting worse from there. Time was called twice in the round to treat cuts suffered by Nemouchi, with the fight ultimately stopped at 2:45 of round one. 

All of the quarterfinal bouts will take place Sunday. The four winners will advance to the medal round. 

Jake Donovan is a senior writer for BoxingScene.com. Twitter: @JakeNDaBox