Surgeons have successfully removed his tumor and are now suturing his incisions, his family told Tuoitrenews at 7:15pm.
Overall condition for Hai is stable and he is still holding well and the operation is expected to be done at least at 9pm (Vietnam time), the family said.
Hai's family memebers and friends, who had left Da Lat central highlands province, Hai's hometown, for Ho Chi Minh City to pray for him, burst into tears of happiness after being told that Hai has survived the operation.
The 32-year-old, who has a 90kg tumor on his right leg, was operated on at 9:00am on January 5, 2012 at FV Hospital located in District 7 in which American doctor Mc Kinnon is the main surgeon.
Hai was sent to the recovery room at 9:15pm the same day when the historic operation was officially finished.
"Dr. McKinnon told my mother that the surgery has ended successfully and my brother is likely to regain his consciousness tomorrow (Friday) morning when she can talk to him," Nguyen Duy Sang, Hai's biological younger brother, told Tuoitrenews over phone.
Hai's tumor is believed to be the largest recorded in Vietnam and probably in the world, too.
The operation had been earlier expected to last from 10 - 12 hours.
"Congratulations and Thanks Dr Mckinnon, FVH team and all friends involved in this walk of hope with Hai and his family," Sam-Ottawa, a reader, says.
"I’m sure millions of people around the world are happy for Hai and his dear family," he added.