Anthony Ogogo got Great Britain's boxing team off to a perfect start with a convincing 13-6 win over Junior Castillo of the Dominican Republic.
The 23-year-old middleweight made a cagey start to his opening contest at ExCel before pulling away in the final two rounds.
Ogogo's build-up was hampered by his mother being taken seriously ill six weeks ago, while his eldest sister Leanne went into labour on Saturday with her second child.
However, the Lowestoft fighter said his mother's fight inspired him to produce a strong and focused performance.
"My mum has given me the belief that if she can come back from where she was and get better, I can win the Olympics. My will has been intensified because of what my family has been going through," Ogogo said.
"They are in the same hospital [in Gorleston]. My sister is just down the corridor so she can take the baby to show my mum.
"I am going to make a run back to Norfolk and hopefully I will have a new niece."
The comfortable triumph sets up a mouth-watering bout against reigning world champion Evgen Khytrov of Ukraine in the last 16. The two will meet in the ring on Thursday afternoon.
"The draw was unkind to me but it doesn't matter compared to everything that has happened," Ogogo added. "Me and my mum are both working hard. Hopefully I am going to get what I feel I deserve."
Ireland pair John Joe Nevin and Darren O'Neill also safely negotiated their first round bouts.
Captain O'Neill saw off Nigerian Muideen Akanji 15-6 and Nevin won by an even wider margin, dominating Dennis Ceylan of Denmark for a 21-6 triumph.