Satoshi Shimizu's controversial defeat to Magomed Abdulhamidov has been overturned by the Amateur International Boxing Association (AIBA).
An investigation was launched following an appeal from the Japanese camp over the bantamweight's 22-17 loss at the ExCel Centre on Wednesday night.
Abdulhamidov fell to the floor on five occasions in the final round, while also incurring a two-point penalty, as Shimizu piled on the pressure.
However, referee Ishanguly Meretnyyazov of Turkmenistan failed to issue a count.
AIBA have now confirmed that Shimizu will take the Azeri's place in the quarter-finals.
The governing body also announced that the referee may suffer a sanction, while the judges have been asked to explain their 10-10 scoring of the final round.
A statement read: "After reviewing the video of the bout involving bantamweights Satoshi Shimizu and Magomed Abdulhamidov, the competition jury made the following decision:
"The boxer from Azerbaijan fell down six times during the third round. According to our rules, the referee should have counted at least three times. In this case, following the AIBA technical & competition rules, the decision should have been RSC (referee stop contest);
"Therefore the protest lodged by the Japanese corner is accepted and the result of this bout overturned. AIBA officials will consider on Thursday morning whether to sanction the referee of this bout."
Shimizu will now take Mohamed Amine Oudahi, from Algeria, on Sunday.