By Jake Donovan

Quanitta “Queen” Underwood made history as the first female boxer from the United States to officially fight in an Olympic boxing match. The bad news is that her opening round draw came against the house fighter against whom she's already lost.

History repeated itself,as Natasha Jonas made it an even 10 in the win column for Great Britiain with a 21-13 victory over Underwood in the first bout of lightweight Round of 16 competition. 

The fight began close, featuring a rare round in which Great Britain lost thus far in the 2012 London Games. Jonas overcame a 4-2 deficit to rack up points in the ensuing rounds, patiently sitting and catching Underwood coming in. 

Underwood kept coming forward throughout the contests, but her leaky defense proved to be her undoing. A questionable standing eight-count in the final round sealed her fate, though one she saw coming once she fell behind in round two.

"I switched up the tactic," Underwood noted in watching an early lead disappear. "She was catching me doing more movement. Being down a point, you can't let the score get to you but I think it got to me a bit. I threw all of the game plans out the window and got caught not having more of a tactic in there."

Jonas' win gives Great Britain nine fighters now in the quarterfinals, as the hosting nation is 11-1 in 2012 Olympic boxing competition thus far. Jonas has the toughest road of the three female fighters; her next opponent is the divisional top seed, Katie Taylor of Ireland.

New Zealand only sent over two fighters in 2012 Olympic boxing competition, none of them on the men's side. An hour after watching teammate Siona Fernandes bow out in her flyweight bout, Alexis Pritchard is her nation's last remaining hope for a medal. 

Helping her cause was some curious officiating on both sides of the ropes, as Pritchard advances to the quarterfinals with a 15-10 win over Tunisia's Rim Jouini.

There was little separation between the two early on, but things went south for Jouini after suffering a questionable two-point penalty in the third round. Pritchard took the four-point margin in the round and rode it out to the finish line, though also benefiting from a blown knockdown call that was instead ruled a slip in the final round.

Pritchard next faces Sofia Ochigava of Russia, who took the silver in the World Amateur championships earlier this year.

Adriana Araujo of Brazil powered her way to a 16-14 win over Kazakhstan's Saida Kassenova, in a fight that was a bit more decisive than indicated in the final score.

Things began slow for Araujo, who took a round or so to settle in before taking over the fight. Kassenova offered a respectable effort, but quickly found herself outgunned. 

The Kazakh fighter also found herself defenseless towards the end of the fight. A verbal "break" command issued by the out-of-position referee was noted by Kassenova but went undetected by Araujo, who landed at least two clean head shots. Two points were added to Kassenova's scorecard as a result, but only made the fight a little closer than should have been the case.

Araujo exploded into celebration the moment she was declared the winner, before settling down and embracing her opponent. The Brazilian lightweight moves on to Monday's final eight action, where she will face idle  Mahjouba Oubtil of Morocco.

China's Dong Cheng overcame some strange officiating to advance to the quarterfinals with a 10-5 win over Mihaela Lăcătuș of Romania.

Cheng was in control for the most part, but the same could not be said of the referee. A clinch towards the end of the fight saw Lăcătuș wrap up Cheng's arm while throwing a series of head shots. The referee intervened, but to issue an eight-count to Cheng rather than penalize Lăcătuș two points for the infraction.

The sequence proved moot as Cheng had a sizable enough lead to overcome the inexplicable call. She now advances to Monday's quarterfinals, where she will face  Mavzuna Chorieva of Tajikistan.

Round of 16 Matchups (Sunday, August 5):
Natasha Jonas (Great Britain) def. Quanitta Underwood (USA), 21-13
Dong Cheng (China) def. Mihaela Lacatus (Romania), 10-5
Adriana Araujo (Brazil) def. Saida Khassenova (Kazakhstan), 16-14
Alexis Pritchard (New Zealand) def. Rim Jouini (Tunisia), 15-11

Flyweight Quarterfinals (Monday, August 6):
Katie Taylor (Ireland) vs. Natasha Jonas (Great Britain)
Mavzuna Chorieva (Tajikistan) vs. Dong Cheng (China)
Mahjouba Oubtil (Morocco) vs.  Adriana Araujo (Brazil)
Sofya Ochigava (Russia) vs. Alexis Pritchard (New Zealand)

Jake Donovan is the Managing Editor of Boxingscene.com. Follow Jake on Twitter: @JakeNDaBox