Sam Harvey has made history.

He has won a last-man-standing backyard ultra marathon in 43 hours, covering a distance of 288 kilometers- unbelievably just 10 days after tying the world record for running 101 hours where he covered 677kilometers in Australia.

The Krayzie Midwinter Backyard Ultra kicked off at 7:30 AM on Saturday in Christchurch, and ended at 2.20am on Monday with Sam beating his race partner to make history by completing 43 laps to raise money for youth mental health charity I Am Hope.

But Harvey's historic win didn't come without everything almost falling apart at the start.

'I almost failed. I went too hard at the start and then spent all day on Sunday thinking I wasn't going finish the race or win. I went to a dark place. Then I just decided to beat the shit out of myself and even if I wasn't going to win, to give my soul a bit of a thrashing for letting my ego get the better of me early in the race.

'I did that for so long that I forgot there was a race going on in the background, and soon there was only five of us left. I knew if I could take these men into their second night there would be a good chance most of them would drop off and they did.

'It ended up being just me and the same guy who came second to me at last year's race. I had to hide my horribly injured Achilles', because if he had made me run another two hours, it would completely rupture,” says Harvey.

In backyard ultras, competitors must consecutively run a circuit of 6.7 kilometers every hour. To get breaks for food, rest and medical attention they must cover the distance before the hour. The faster they cover the distance, the longer they get to rest.

'Sam's achievement is astonishing. He has redefined the limits of human endurance, mind and body. Despite facing doubts and dark moments, his relentless determination propelled him forward, to support Kiwi kids who need help.

'It's a great lesson in just pushing forward when all odds are stacked against you. When he went all out at the start he had to face the very real possibility of public failure and letting the people he cared about down.

'He thought he would be letting us down. But he just decided to pushed through the pain, lap after lap. And guess what? It paid off. When you feel like everything is going against you, just put one step in front of the other,” says I Am Hope founder Mike King.

Harvey raised $20,000 for I Am Hope when he competed at Dead Cow Cully in Queensland just 10 days ago, garnering international attention. But he is not done yet, with plans to complete in the Big Dog's Backyard Ultra in Tennessee, America later this year.