After taking the baton from his teammate Yohan Blake to run the anchor leg of Jamaica's 4×100-meter men's relay, Bolt began to gather speed only to pull up and shout in pain from what appeared to be a left leg injury about 60 meters from the finish line.
It was hardly the farewell party that Bolt, the greatest sprinter in history, had in mind when he decided to make this meet the last of his career.
His apparent injury would normally have cast a pall over the rest of the race, but it has been a frustrating meet for Britain, the host country. And with Bolt on the ground and the Jamaicans out of contention, the gold came down to a sprint for the finish between Christian Coleman of the United States and Nethaneel Mitchell-Blake of Britain.
Britain won by 0.05 seconds, finishing in 37.47 seconds to the Americans' 37.52. As the official results flashed on the big screen, the crowd cheered wildly for Britain's second gold medal of these championships.
Meanwhile, Bolt's teammates rushed to help him as he lay on the track.