KINGSTON, Jamaica — With the London Olympics 82 days from commencing, a glittering cast of medal contenders converged at the Jamaica International Invitational on Saturday to test their progress while Jamaica’s avid track and field fans came to see their sprinters compete on home ground. The undisputed star of the meet — and unofficial host for his country — was Usain Bolt, who cruised to victory in 9.82 seconds in his first open 100-meter race of the season. Bolt managed a promising time despite the aggravation of two false starts that brought the runners back to the starting line. After the race, Bolt took off his electric-green spikes and jogged past the bleachers, slapping palms with delirious fans inside the packed and deafening National Stadium. Bolt, who won three gold medals and set three world records at the 2008 Olympics and holds the world record of 9.58 seconds, ran a 9.76 here before the Beijing Olympics. “I think I could have done better, but the false starts didn’t help my focus,” he said. “It’s a good start for my first run. It’s a great feeling to run in Jamaica.” Bolt’s main challenger for another Olympic sweep is training partner and countryman Yohan Blake, who has come on strong after a drug suspension three years ago. Blake, who ran a world-leading 9.80 in the 100 last month here in the rain, elected not to race against Bolt and won the 200 meters, smoothly pulling away from two teammates to finish in the world-leading time of 19.91. On a breezy night, storm clouds hung over the mountains behind the stadium. Jamaica’s athletes felt right at home in the humid conditions. Spectators waved the yellow, green and black flag of the island nation, which is celebrating its 50th year of independence. The meet enhanced the U.S. vs. Jamaica rivalry. Jamaica’s sprinters have overtaken the Americans in recent years and they dominated the glamour speed events at the Beijing Games. Both the Jamaican and U.S. track and field teams will be based in Birmingham, England, for their pre-Olympic training camps. Two athletes with South Florida ties gauged their readiness to win more Olympic medals. For Sanya Richards-Ross, the meet was like a homecoming. She spent her childhood in Jamaica before moving to Pembroke Pines and graduating from Fort Lauderdale St. Thomas Aquinas High. Richards-Ross, who lives in Austin, Texas, was accompanied here by her parents and husband Aaron Ross, a New York Giants cornerback who earned a Super Bowl ring three months ago. “It’s always wonderful to come back and see family and friends,” she said. “I feel very comfortable here.” Richards-Ross, consistently ranked No. 1 in the 400 meters, was overtaken in the last 50 meters by Jamaica’s Novlene Williams-Mills, who won with an impressive time of 49.99. Richards-Ross was second in 50.11, ahead of England’s Christine Ohuruogu, who upset her for gold in the Beijing Games. “My training is going really well, but Novlene had a better kick,” Richards-Ross said. “Of course I’m disappointed, but it’s my first race of the year so I’ve got time to get better.” Miami’s Bershawn “Batman” Jackson held on to win the 400-meter hurdles in 48.73 despite nicking the seventh, eighth and ninth hurdles with his trail leg.