Following are the results in quarter-final bouts in the Olympic boxing tournament on August 23:

Heavyweight (over 91kg)

Michel Lopez Nunez (Cuba) beat Jason Estrada (United States) points 21-7

Mohamed Aly (Egypt) bt Jaroslav Jaksto (Lithuania) points 19-11

Roberto Cammarelle (Italy) bt Oleksii Mazikin (Ukraine)points 23-21

Alexander Povetkin (Russia) bt Mukhtarkhan Dildabekov( Kazakhstan) points 31-15

Featherweight (57kg)

Kim Song-Guk (DPR Korea) bt Muideen Ganiyu (Nigeria) points 32- 11

Vitali Tajbert (Germany) bt Luis Franco Vazquez (Cuba) points 34-26

Jo Seok-hwan (South Korea) bt Viorel Simion (Romania) points 39- 35

Alexei Tichtchenko (Russia) bt Galib Jafarov (Kazakhstan) points 36-26

Bantamweight (54kg)

Bahodirjon Sooltonov (Uzbekistan) bt Andrew Kooner (Canada) points 44-32

Guillermo Rigondeaux Ortiz (Cuba) bt Gennady Kovalev (Russia) points 20-5

Worapoj Petchkoom (Thailand) bt Nestor Bolum (Nigeria) points 29-14

Aghasi Mammadov (Azerbaijan) bt Maksym Tretyak (Ukraine) points 32-12