Zac Wilson and Dimitri Mardari were driving back from a night out at about 4am on New Year's Day when they saw a crumpled black Mercedes in a ditch on the Bath Road in Knowl Hill.
Dad-of-one Zac, of nearby Choseley Close, said the pair could hear the engine still revving when they pulled over and saw a man trapped inside the vehicle and covered in blood.
"I called 999 straight away and they told us not to move him because he might be badly injured," said the 35-year-old.
"We couldn't turn off the engine and after a few minutes smoke filled the car and things started to catch fire.
"That's when we knew we only had a few minutes to get him out."
The former Piggott School pupil said he held back branches pressed against the car as his 25-year-old cousin, from High Wycombe, struggled to pull the driver through a smashed back window.
The pair managed to carry the 34-year-old man, who police confirmed is also from Knowl Hill, out of the ditch only seconds before the car exploded.
"We just saw a huge ball of flames and then everything was on fire," said Zac, who works as a driver for Grundon Waste Management Ltd based in the village.
"Looking back it was very risky but I couldn't leave him in the car to burn, I wouldn't be able to live with myself.
"Instinct kicked in and we did what we had to do to get him out.
"We were all lucky to get out alive."
Maidenhead firefighters arrived on the scene shortly after 4.07am and said the blaze had completely engulfed the car.
"Whoever pulled the man from the car saved his life," said watch manager Nigel Slatt.
"He was lucky there was someone nearby at that time in the morning."
The crew spent two hours at the scene near the Seven Stars pub, putting out the flames.
An ambulance took the driver to the Royal Berkshire Hospital in Reading. He suffered a broken arm and serious injuries to his neck and stomach.
His condition has been described as critical.
Police are investigating the cause of the crash and are appealing for witnesses.
Anyone with information can call 101 or anonymously on 0800 555111.
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