He chugged in two and a half seconds behind the winner in a preliminary heat — for an event that elite runners don't even take 10 seconds to complete.
Jennet Saryyeva of Turkmenistan was nearly lapped in a swimming heat. Zamzam Mohamed Farah of Somalia completed the women's 400 metres track race in 1 minute, 20.48 seconds — a whopping 30 seconds behind the winner, and no better than a reasonably fit woman in the stands at Olympic Stadium could have mustered.
For athletes from the world's smallest countries, or those suffering through conflict and turmoil, the Olympics are not about winning, but there is victory and honour in just showing up.
Perhaps no competitor exemplifies that spirit more than Farah, whose training regimen consisted of early-morning jogs through the streets of war-ravaged Mogadishu, where she had to navigate roadblocks manned by competing militiamen.
"Sometimes the soldier on guard would mistake us for being suicide bombers or attackers, and they would order us to stop or they would shoot," she told The Associated Press in a July interview.
The 21-year-old's time in the 400 metres in London was just two seconds better than the world mark held by American Jean Daprano — the world mark in the women's 75-and-older category.
Nonetheless, she was cheered back home, where talk of her accomplishment was mixed with pride, and nostalgia for a time when the country's name was not synonymous with chaos, piracy and early death.
"We are very proud to have taken our flag to the world stage," said Liban Yusuf, who lives in Mogadishu.
Abdirizaq Mohamud, another city dweller, said he hoped Farah's time would be the first step on a path back to respectability.
"We could surprise many people if we got better results, so that we could reclaim our reputation," he said, and it was clear he meant more than just sports.
Many athletes from the world's forgotten or forlorn countries came to the Olympics via wild card berths granted by international sports federations, part of a drive to include as many countries as possible in the games.
Some 204 nations are represented in London, 11 more than there are member states at the United Nations, and four athletes are competing independently under the Olympic flag.
Sometimes, having such a large field stirs controversy. There have been protests against a Syrian equestrian rider who has voiced support for President Bashar Assad, whose forces have killed thousands in a bloody civil war.
And hardline Saudi clerics — as well as some sports purists here in London — have decried the participation of a novice Saudi judo fighter in a field of high-level black belts. The former said she was defiling Islam, the latter the sanctity of sport.
But it is also a chance for athletes to push cultural boundaries. Who knows whether there is a little girl in Afghanistan right now who will be inspired by Tahmina Kohistani, who finished her women's 100-metre heat in a molasses-like 14.42. Kohistani has talked about being kicked out of taxis by male drivers who disapproved of her ambitions, but also of the importance of her carrying on.
"I hope the next generation of women will be proud of me and that they will never forget me," she said.
For Garstang, the Marshall Islands sprinter, the Olympics has been more about meeting Jamaican sprinter Usain Bolt, who broke the Olympic record in the 100-metre final Sunday night, than competing against him.
Garstang ran into Bolt in the athletes village but said he was too shy to introduce himself. He also acknowledged a strong case of nerves when he lined up in his heat before 80,000 screaming fans at Olympic Stadium. And who can blame him?
"There were more people there than in my entire country," he said, and he wasn't exaggerating. The Pacific island nation has a population of 68,000. And it's not just athletics and swimming that have produced unusual results from unlikely competitors.
Anolyn Lulu carried the hopes of teeny Vanuatu with her into her preliminary-round table tennis match against Brazilian Ligia Silva, only to go down 4-0. Games are usually played to 11 points. Lulu's best score was nine, and she was crushed 11-2, 11-3 and 11-5 in the other games.
Niger's Hamadou Djibo Issaka, a rower who had trained only three months, and in an old fishing boat, was cheered enthusiastically start to finish in the men's sculls, though he came in last of 33 competitors, a full minute behind his nearest competitor.
It was not a bad finish when you consider that Niger is a landlocked country that is 80 per cent desert. And Issaka surely led the field in nicknames acquired along the way, including Issaka the Otter and the Sculling Sloth.
Some have questioned the participation of athletes like Issaka, who are clearly outmatched and taking the spot of someone else who is faster, stronger, better. But the International Olympic Committee says their inclusion goes to the core values of the games themselves, which are about not just winning or losing but inspiring a better and more harmonious world.
"You have to balance two things," said Mark Adams, a spokesman for the IOC. "Clearly, this is about elite sport, but it is also about sport for all. You don't want it to be a farce, but one of the things people love about the Olympics is that we get everyone involved. It doesn't spoil the competition for people. They give a huge cheer."
Associated Press writer Abdi Gubed contributed from Mogadishu, Somalia.