Xuan Son (number 12) made a breakthrough on the right wing into Thailand's penalty area in the 32nd minute.
Moving at high speed, as he attempted a back pass, his right leg struck the ground, causing it to bend and break despite no contact with anyone.
The Brazilian-born striker appeared to be in severe pain, clutching his leg, screaming, and signaling for medical assistance.
Striker Pham Tuan Hai rushed over to check on his teammate.
Slow-motion replay on television revealed that Son's right ankle was severely disfigured.
The referee quickly recognized the severity of the situation and called for a stretcher to be brought onto the field.
Due to the intense pain, Son was unable to get onto the stretcher by himself and had to be lifted by the medical staff.
The 27-year-old striker covers his face. It seemed he was not only in pain but also aware of the severity of the injury.
His teammates rushed over to console Son.
Vietnam was forced to make a substitution, bringing in Nguyen Tien Linh as a replacement. The score at that point was 1-1.
Before leaving the field, Son was tightly marked by Thai players and had little opportunity to make an impact.
In the first leg, he had scored two goals against the War Elephants.
