Women's boxing made its Olympic debut on Sunday as British lightweight Natasha Jonas vowed not to be intimidated when she faces Irish world champion Katie Taylor in Monday's quarter-final.
With women competing in the fly, light and middleweight categories for the first time at an Olympics, Jonas dug deep Sunday for a hard-earned 21-13 first-round win over Quanitta Underwood of the USA.
The top seeds all have byes into the quarter-finals and four-time world champion Taylor now faces Jonas for a place in Wednesday's semi-final at London's ExCel Arena.
Having lost 6-3 to the Irishwoman when the pair fought in Bulgaria last year, Jonas has vowed to raise her game.
"My next fight is against the world champion, but I made a few mistakes in my opening bout and I will work on them," said Liverpool's Jonas, who was behind in the first round before claiming a convincing win over Underwood.
"It is unfortunate it has come this early, but one of us has got to win.
"I gave her too much respect the first time I boxed her, I was a bit in awe of her reputation, but times have changed and I am a different boxer."
On the other side of the lightweight draw, second-seed Sofya Ochigava of Russia will face Alexis Pritchard of New Zealand in her quarter-final after her 15-10 win over Tunisia's Rim Jouini.
In the flyweight division, five-times world champion M.C. Mary Kom of India showed great early form for a dogged 19-14 win over Poland's Karolina Michalczuk.
Kom, has stepped up from light flyweight and was in tears after her victory -- on her twin sons' fifth birthday.
"It is a very emotional day for me," said the 29-year-old.
"Every athlete wants to compete at the Olympics and I have been waiting 12 years for this chance to fight here.
"It's my sons' fifth birthday and I can't be with them today."
Kom faces Tunisia's Maroua Rahali in her last eight bout, while world champion Ren Cancan of China will take on Russia Elena Savelyeva, who won the historic first bout of the day 12-9 against Kim Hye-Song of North Korea.
Like Rahali, home favourite Nicola Adams had a bye into Monday's last eight clash where she will face Bulgaria's Stoyka Petrova, who enjoyed a 23-11 win over New Zealand's Siona Fernandes in their bout.
British world champion Savannah Marshall is the middleweight name and she faces Kazakhstan's Marina Volnova, who dominated Kenya's Elizabeth Andiego for a comfortable 20-11 win.
Elena Vystropova of Azerbaijan, who Marshall beat in May to win the world title, suffered a first-round exit as she was upset by Nigeria's Edith Ogoke who won three of the four rounds for a deserved 14-12 victory.
Ogoke will now face second-seed Nadezda Torlopova of Russia in Monday's quarter-final.
"Most of the Nigeria men have already gone home, so I want to keep the flag flying," said the 22-year-old.