LONDON — After an unforgettable performance in the 4x100-meter relay, Usain Bolt of Jamaica wanted a souvenir with which to remember his second Olympics. His grip tightened around his object of choice: not a trinket featuring the London Games’ omnipresent one-eyed mascots, but the baton he had received from his training mate, Yohan Blake, and carried across the finish line in world-record time moments earlier.


The Jamaican team that Bolt anchored had set a world record of 36.84 seconds to edge the United States squad, which tied the Jamaicans’ previous world mark of 37.04. Only after he had secured his sixth gold medal in two Olympics, completing a triple-double more impressive than any posted by a United States Olympic men’s basketball Dream Teamer in 1992 or now, did Bolt lose a piece of history that he considered his.


An official asked for the baton, and Bolt grudgingly relinquished it. His smile disappeared shortly before he did inside the tunnel leading to and from the Olympic Stadium track. It was no way for a legend to exit the world’s stage, and by the time the medals ceremony was held, Bolt had his baton back.


“He said I have to give it back, or the relay would be disqualified,” Bolt said. “That was kind of weird.” He added, “I guess somebody talked to the guy and said you need to give him the baton.”


Bolt did not need the baton to make like a conductor and lead the crowd in the wave after the playing of Jamaica’s national anthem, a gesture that was Bolt at his sportive best. In a competition in which medal counts and other nationalistic displays often take center stage, it took a showman of Bolt’s stature to twice take the Games by storm and remind people that sports, even at its highest level, is child’s play.


Bolt, 25, become the first man to successfully defend his 100- and 200-meter titles and he helped Jamaica become the first country to successfully defend its men’s sprint relay title since 1976. The first and only other time a track and field athlete won three events at consecutive Olympics was in 1904, when Ray Ewry won the standing high jump, the standing long jump and the standing triple jump.


Bolt’s not one to stand around. He was animated in the minutes before the relay, flexing his muscles in a Mr. Universe pose and shooting an invisible arrow into the Olympic Stadium crowd, which cheered Bolt and his teammates as if they were Britons. Bolt, in particular, got the same roar as Britain’s Mo Farah, who earlier in the night had added the 5,000 title to his 10,000 crown.


Bolt wore a stocking cap onto the track to ward off a chilly breeze. After Blake ran down the American Tyson Gay on the third leg, giving Bolt a slight lead, he ran faster than any wind. The lengthening lead was a familiar sight, but Bolt gracing the last leg was not; he ran third in 2008 but was forced into the anchor role because of an injury to Jamaica’s usual closer, Asafa Powell.


The American anchor, Ryan Bailey, ran well but could not keep pace with Bolt. Who could? Asked if his performance would have been good enough to overtake any other sprinter in the world, Bailey smiled and said: “That’s tough to say. Bolt, he’s an animal, he’s a beast. Once he opens his stride up, it’s tough to stay with him. I just ran my heart out.”


So did Allyson Felix, who ran the second leg of the women’s 4x400 relay. She ran 47.8 to lead the United States to its fifth consecutive gold medal in the event. Felix, DeeDee Trotter, Francena McCorory and Sanya Richards-Ross were timed in 3 minutes 16.87 seconds, tantalizingly close to the 24-year-old world record of 3:15.17.


Felix was an integral part of the Americans’ world-record-setting 4-x-100 team on Friday, and Trotter was primed for an encore.


“I was trying to amp them up,” she said of her teammates. “In my mind, this world record, if any team can do it, this one could. I consider us the Dream Team of the 400. We were definitely gunning for the record.”


So were the Jamaicans, who set the previous men’s mark last year. “Basically, we are not human,” Blake joked. He added, “We are not normal guys. We are from space.”


They are prone to acting spacey. As Bolt crossed the finish line, he folded his arms in a heart shape over his head, imitating the signature move of his friend, Farah, who had earlier stolen Bolt’s signature arrow gesture. After the 200 meters, Bolt dropped down and performed a few push-ups. So after the 5,000, Farah dropped down and did a few situps, which raises the question: What will Bolt do next?


He did not sound like someone with a third Olympics in his future. “I think at the age of 30, it’s going to be hard to do great things,” Bolt said. “I’m just going to enjoy the moment. I did what I came here to do.”


After the 200, Sebastian Coe, a former track star and the chief of the London Olympic organizing committee, called Bolt a legend. With his performance Saturday night, set against a circle of camera flashes, Bolt proved himself to be part-man, part-myth and wholly unique.


“There will never be another like him,” Farah said. “We take him for granted, but he’s absolutely amazing.”