Footy fan loses bet on an AFL game - and now he has to walk from Los Angeles to San Diego

A footy fan in the United States is set to pay a heavy price after putting an enormous bet on the AFL in Australia and losing in spectacular fashion.

The Sydney Swans were expected to make light work of cellar dwellers St Kilda at Marvel Stadium on Sunday with most bookies having them at almost odds-on favouritism to beat the struggling Saints.

Americans Watching The Footy is a social media channel and podcast run by brothers Benjamin and Ethan Kassel who break down AFL games for a US audience. 

Benjamin was so sure that Sydney, who had only tasted defeat twice all season prior to the match, would beat St Kilda he said that he would walk from Los Angeles to San Diego if the biggest upset of the year came to pass.

Then the unthinkable happened. Trailing by more than 30 points at one stage, the Saints launched a spirited comeback and prevailed by just two points to record their fifth win of the season.

That means Benjamin has a long walk ahead of him.

'In our round preview, I said that if the Saints won, I would walk from San Diego to Los Angeles,' he said.

'I'm a man of my word. It'll probably be in December, during my winter break.'

Kassel now faces an arduous 50 hour foot journey along the Transamerica Highway following St Kilda's thrilling victory.

'134 miles (~216 kilometers). I'm up for it,' he posted.

He called the loss his 'Jim Rooker moment', after the American baseball player who infamously said on air as a broadcaster that he would walk home to Pittsburgh if the Pirates lost.

The Pittsburgh Pirates had taken a 10-0 lead in Philadelphia, only for the Phillies to storm home 15-11 winners. 

While Rooker did not walk home that day, he did honour his word and organised a charity walk from Philadelphia to Pittsburgh - a distance of 490km.

St Kilda coach Ross Lyon revealed post-match that the battling club had some help from cross-town NRL rivals the Melbourne Storm leading up to the shock victory.

After making the finals last year, the Saints are 6-10, and even with Sunday's big upset the top eight looks beyond them this season.

Lyon said the relationship with the Storm is 'a blessing'.

'We can't get stuck in win-loss, it's about training, (preparation), standards and setting a foundation for future success,' he said.

'We just know it's unlikely, and probably impossible, to play finals - but how we go about it now, train and prepare and compete and review, will set standards for future success.'