The video, captured at Al Maktoum Stadium by a Vietnamese fan, shows defender Brendan Gan committing the foul in the penalty area in the 80th minute of the game, stepping on Toan's left leg from behind, causing the Vietnamese striker to fall.
Japanese referee Sato Ryuji saw the foul and immediately pointed to the spot despite vociferous opposition from some Malaysian footballers. Que Ngoc Hai scored with the penalty kick and raised the score to 2-1 for Vietnam.
After the match, Malaysian media ran reports suspecting that Van Toan had dived when the TV camera's angles at that time were not long enough to capture the whole incident.
In an interview with VnExpress on Saturday, Toan affirmed that he did not cheat but was actually fouled from behind.
"When I just entered the penalty area and put my right foot to control Van Thanh's pass, the Malaysian defender kicked my left heel. I didn't pretend to fall and earn a penalty kick. The opponent fouled me and the referee was right to give Vietnam the penalty kick," he said.
Vietnam's next World Cup qualifier opponent are the UAE, ranked 70th in FIFA with 1351.71 points. A draw against the UAE on June 15 should be enough for Vietnam to advance to the final qualifiers of a World Cup for the first time.