Rather than getting the spikes cut out of his foot, which would have meant a plane ride home, Tobin battled on with the help of antibiotics and painkillers.
He admits he struggled in some races, but by the end of the week he had found his rhythm again, pulling out a strong performance in the medal race to overtake Ashley in the standings.
In the end just one place separated the two great rivals.
Tobin knows better than most that the line between success and failure is slim. As an 18-year-old he missed out on the Atlanta Games, but admits he was slightly out of his depth against Bruce Kendall and Aaron McIntosh. He thought he was a good chance for Sydney in 2000, but lost out to McIntosh, who is now his coach.
His bid for the 2004 Games ended with an unsuccessful appeal to the Sports Tribunal, after selectors opted to send Ashley to Athens, despite Tobin qualifying New Zealand the spot. Ashley again got the better of Tobin in 2008.
So how did Tobin feel when he got the call he'd been waiting almost 16 years for?
"Absolute elation," he said. "It's been a long road, but I always had the belief and to have it finally come true is really exciting."