Anthony Ogogo got the Great Britain boxing team off to a winning start at London 2012, comfortably beating Junior Castillo Martinez at the ExCel Arena.
The 23-year-old middleweight, from Lowestoft in Suffolk, recovered from a slow first round against his awkward Dominican opponent to advance comfortably, by 13 points to six.
Ogogo faces top seed and reigning world champion Ievgen Khytrov in the last 16.
Irish pair John Joe Nevin and Darren O'Neill also advanced.
With Hull bantamweight Luke Campbell receiving a bye into the second round, Ogogo was charged with igniting his country's boxing campaign.
And having overcome so many obstacles in order to get to London, Ogogo's overriding emotion after seeing off Martinez was relief.
"It was really nerve-wracking coming out first," said Ogogo, whose Olympic dream was nearly wrecked by a shoulder injury and whose mother, Teresa, suffered a brain haemorrhage six weeks ago.
"I've worked so hard to get here and you can only imagine what it's going to be like, so I was a bit tense in the opening round before settling down a bit in the second.
"I can't wait to ring my mum up and tell her. My sister also went into labour today, so it's been a great day for the family.
"The draw's not been very kind to me. I've got the world champion next, the Ukrainian, but in front of this crowd I feel like I can beat anybody.
"I've never boxed [Khytrov] before and it's going to take a momentous effort but I feel I've got it in the locker to beat him."
Fifth-seeded bantamweight Nevin, from Mullingar in County Westmeath, comprehensively outboxed Denmark's Dennis Ceylan to win 21-6.
Nevin, twice a World Championship bronze medallist, is part of a six-strong Irish team looking to improve on a tally of three medals in Beijing.
The 23-year-old faces Kanat Abutalipov in the next round after the Kazakhstani beat Wessam Salamana, one of only 10 Syrian athletes competing in London, 15-7.
Nevin's 56kg rival Campbell begins against Jahyn Vittorio Parrinello of Italy, who beat Namibia's Jonas Matheus 18-7.
The Briton could meet former world champion Detelin Dalakliev, who beat, Ayabonga Sonjica in the quarter-finals.
Campbell beat the Bulgarian in the European Championships final in 2008 to become the first Briton to win a European title since 1961.
Irish middleweight O'Neill, a European silver medallist in 2010, beat Nigeria's Muideen Akanji 15-6 and faces Stefan Hartel of Germany next.
Londoner Isaac Dogboe, representing Ghana, had a two-point lead heading into the last round against Japan's Satoshi Shimizu, but the 17-year-old ended up on the wrong end of a contentious 10-9 verdict.
Joseph Diaz of the United States had the honour of winning the first bout of the tournament, the 20-year-old southpaw outpointing Ukraine's Pavlo Ishchenko 19-9.
Diaz's reward is a bout against Lazaro Alvarez Estrada, the top seed and reigning world champion from Cuba, who received a first-round bye.