Vietnam's coach Park Hang-seo said at a press conference on Friday that Vietnamese players have worn out after five group stage matches and they will have to rely much on their fighting spirit.
"It will be a difficult game for Vietnam as Cambodia had one less group stage match in group A and has had one extra day to rest," he said.
Eliminating arch rivals Thailand on Thursday, Vietnam entered the semifinals as top of group B, while Cambodia, second in group A, are in semifinals for the first time in SEA Games history.
Coach Felix Dalmas recognized Vietnam's strength but said he's confident in Cambodia.
"This will surely be Cambodia's biggest challenge in the tournament thus far, but we can overcome this. We need to prepare carefully and bring our best spirits and biggest ambitions into the game," Dalmas said.
"Vietnam are very strong, but they have imperfections. We believe in our chances."