"As I opened the door and was trying to get him up to get him out, the car essentially caught fire."
Del said the victim was knocked out and he had to jolt him awake to try to get him out of the vehicle.
"His head was just on the steering wheel. I had to shake him a bit and stuff like that and say 'get out'.
"I genuinely think he would've stayed in the car.
"I said to the guy: 'Look, the car's on fire. You need to get out, otherwise this thing is gonna blow up'."
Del said he and another member of the public managed to get the victim on to the ground and move him away from the burning vehicle.
"It was pretty scary. I've never been in that situation before. At first, I was a bit taken back.
"I wasn't quite sure what to do - if I open the door, what am I gonna see? But yeah, I built up enough courage to open the door and pull the dude out."
Images of the white car show the front of it completely smashed in and twisted around the traffic light pole. The inside is scorched black.
A police spokeswoman told the Herald a man suffered serious injuries in the crash and was taken to Middlemore Hospital for treatment.
Counties Manukau road policing manager Inspector Kay Lane said the serious crash unit is continuing to investigate the incident.
"Police would like to acknowledge the great actions of a member of the public who was first on scene in the early hours of this morning," she said.
"Not only did he stop after coming across a crash, but he also put aside his own personal safety to intervene and helped to pull the driver from the vehicle before it caught fire.
"His actions in no doubt assisted emergency services this morning."
NZ Fire and Emergency shift manager Daniel Nicholson said when firefighters arrived, the car was "well involved".
Fire crews quickly extinguished the blaze and left the scene with Police and St John paramedics.
At the scene, Del praised the man and woman who stopped to help after several vehicles failed to stop to help.
"There were probably about 10 cars that drove past and I was waving to them because I wanted some support and some help at that moment - and hopefully, someone bigger than me would come in and help me as well.
"They sort of slowed down, looked and drove off. That's very disappointing. I don't know why [they didn't stop]."
He thanked the man and woman who stopped to help not only the victim but him.
"If you're gonna say anyone's heroes, they're also heroes - because they pulled over and stopped."
As a result of the crash, Great South Rd between St George St and Tui Rd was closed for some time as authorities worked at the scene.
Auckland Transport said just before 7am that the road was now clear and had been reopened. Motorists are, however, being told to allow for extra travel time heading west.
Traffic signals in the area are damaged and a police pointsman is directing traffic as a result.
Meanwhile, emergency services in West Auckland were called to another car fire at a property on Canal Rd in Avondale.
Two fire trucks were sent to the scene just before 1am.
Fire crews found the car was well involved in flames and, as a result, the fire had spread to part of the house.
Authorities said both fires were quickly put out and a fire investigator was looking into the circumstances of the incident. The house was vacant at the time and had been boarded up.
