The Jamaican lost by a hundredth of a second to American Justin Gatlin in the 100 metres Thursday night at the Golden Gala meet. Gatlin finished in 9.94 seconds.
It was Bolt's first significant loss since his false-start disqualification at the 2011 world championships in South Korea. But he also struggled in his first 100 this year, winning a photo finish in 10.09 in the Cayman Islands a month ago while dealing with a hamstring injury.
This is normally the time Bolt starts to leave his rivals behind as he revs up for the year's biggest event. This season, it's the world championships in Moscow in August.
However, the always cool Jamaican isn't worried.
"For me it is just going through the season," said Bolt, the world-record holder and six-time Olympic champion. "Put things together for the world championships. The season is still very early."
He did not blame the hamstring this time.
"During the race I didn't feel it all," he said. "Afterwards it was sore but that's expected. But during the race it was fine."
Gatlin, who has won all five of his 100-meter races this year and had been doing some pre-race trash talking, was restrained in his celebration, just clapping his hands rapidly.
"This year I just want to be able to put together a better race, give him some competition when he's at his top form, to make it a more epic race," Gatlin said. "He's a legend. He's done great things and I just want to go out there and just fight to the end."
Bolt briefly covered his face with his hands after the race, and then saluted the crowd. After things settled down, Bolt went over and shook Gatlin's hand and congratulated him.
"I came into this race trying to figure out where I was," Bolt added. "Now I just need to go back and watch the tape and see what went wrong and what I need to work on and compete better next time. ... The fact that I lost this race is a good thing."
Bolt struggled in the first 50 metres despite his strong start. He started to gain ground on Gatlin near the finish but would have needed a bit more track to overtake him.
"That was ridiculous — a perfect start and then I just cropped off," Bolt said. "I think it was this perfect start that threw my game off. I have to do more strength work, I guess. I think it needs just some time to get it all back together. At the end it was just not me."
In perfect conditions before a Stadio Olimpico crowd of 52,305, Bolt was second in 9.95 and Jimmy Vicaut of France third in 10.02.
"At least I got under 10 seconds," Bolt said. "My legs did not feel the energy. At 50 metres I had some problems, but the rest of the race was not bad.
"My fifth step I kind of stumbled a bit. The last 50 where I thought I would be much better I wasn't there, so I guess I just need to go home and figure out what I need to do and get it right, because normally my last 50 of the race is my best part. I need to put it together. I have enough time. I'm not worried."
Kim Collins, the 37-year-old from St. Kitts and Nevis, appeared to have a slight lead on Gatlin at the 50-meter mark, but he finished fifth in 10.07. Michael Rodgers of the United States was fourth in 10.04
"When you have someone like Kim in the race he's going to dominate the first 50 metres. You can't get flustered by it. You got to stay in your race pattern," Gatlin said. "The end of the race was more of a blur. I just made sure I kept putting my feet down and that was really what mattered to me."
Bolt also was beaten by Tyson Gay in August 2010 in Stockholm.
"I don't keep count of how many people have beaten Bolt. But I can say it's an honour to be able to race against him," Gatlin said. "He's been an inspiration for the sport. He's brought so much to the sport that it has never had before, so he's inspired me to be a better runner and a better entertainer for the fans."
This was Gatlin's third Diamond League win in the 100 this year. He ran 9.97 seconds in Doha, Qatar, and a wind-aided 9.88 in Eugene, Oregon, last weekend. The wind this time was well within the limit.
Gatlin took bronze at last year's London Olympics to cap his comeback from a four-year doping ban, having won the 100 at the 2004 Athens Games.
"Last year I was a really great starter," Gatlin said. "This year I've been working on my conditioning, trying to get my start back and make sure the middle of my race is stronger. Each race is important."
Bolt will next run the 200 at the next Diamond League meet in Oslo, Norway, next week before he returns home for the Jamaican championships. Gatlin has the U.S. trials this month.
In other events, Russians Anna Chicherova and Svetlana Shkolina — the Olympic gold and bronze medallists , respectively — shared the high jump victory at 6 feet, 6 inches. Two-time world champion Blanka Vlasic took third in her second meeting since returning from a 16-month ankle injury layoff. Vlasic cleared 6-4 3/4 on her third attempt, improving on her winning 6-4 1/4 in New York last month.
There was a surprise in the women's 200 as Olympic champion Allyson Felix was soundly beaten by Murielle Ahoure of Ivory Coast. Ahoure finished in 22.36, while Felix never really threatened and crossed second in 22.64.
In the women's 400, world champion Amantle Montsho of Botswana finished in 49.87 for the best time this year, extending her winning streak in the single lap to five races.