Ireland\'s John Joe Nevin aims to turn bronze to gold when he faces world champion Lazaro Alvarez in the Olympic bantamweight semi-final following his last eight victory on Sunday. The 23-year-old booked his place in Friday\'s semi with a 19-13 quarter-final win over Mexico\'s Oscar Valdez, 21, at London\'s ExCel Centre by dominating the second and third rounds after the first finished all-square. Semi-finalists are guaranteed a medal with both losers walking away with bronze, but having made sure of at least a medal for Ireland, who have yet to win one at these games, Nevin insists he is going for gold. \"It means a lot to me, but hopefully I can turn it into gold,\" said Nevin. \"Alvarez is the world champion, I will just just enjoy this win, that is a story for another day. \"It is like the Queen song, \'I want it all\', I want every bit of it, I want to be the best in the world.\" Although Nevin needed a standing count in the third after being winded by a heavy shot to the side, the Irishman finished strongly. \"Oscar Valdez will make a world champion someday in the professional ranks,\" said Nevin, the fifth seed. \"The right hook got him every time, but he started tiring and missing punches, which takes it out of you.\" Nevin faces a tough task against Cuba\'s world champion Alvarez, 21, who had showed his class earlier with a 16-11 last eight win over Brazil\'s Robenilson Vieira de Jesus in a commanding display. Having fallen behind on points after the first round, Alvarez upped the pace and finished the next two rounds at least three points clear of the Brazilian. On the other side of the draw, Britain\'s Luke Campbell will face Japan\'s Satoshi Shimizu in their semi-final on Friday after the plucky 24-year-old held his nerve for a 16-15 last eight win over Bulgaria\'s Detelin Dalakliev. \"Fantastic, I worked all my life to get this point and this makes all the sacrifices worthwhile,\" said Campbell, 24, the third seed in London who lost the 2011 world championships final to Alvarez. \"This is just the start, I am here for gold. I want to be in that final. \"He was holding me a lot, but I just had to keep calm and let the punches go.\" In the heavyweight division, world champion and Olympic favourite Oleskandr Usyk took his place in Friday\'s semi-final with a 17-13 win over Russia\'s Artur Beterbiev. It was the same score and result from the pair\'s quarter-final clash at last year\'s world championships when Usyk went on to claim gold. Usyk will next face Tervel Pulev in the last four after the Bulgarian\'s 13-10 win over Argentina\'s Yamil Peralta. After his bout with Bulgaria\'s Siarhei Karneyeu finished 19-all, Teymur Mammadov of Azebaijan, the 2011 world silver medalist, went through on count-back and will face Italy\'s Clemente Russo in Friday\'s semi after his 12-10 win over Cuba\'s Jose Larduet.