The Jamaican world record holder, who managed only 10.04 in Ostrava last Friday, was back to his best against a world class field which included his compatriot and former world record holder Asafa Powell.
Powell, who said later he had not heard the starting gun, finished second in 9.91 while European champion Christophe Lemaitre finished strongly to take third place in 10.04 seconds.
Bolt said he had not been sleeping regularly since he arrived in Europe.
"After Ostrava I decided I will make sure to go to bed early and start eating right," he said. "I feel extremely well, so it's coming back and I'm feeling good.
"People expect me to do well all the time and I expect that from myself also, it's not really pressure for me. I came out here tonight not to prove anything but to tell myself I've still got it.
"The race was much better than in Ostrava. After Ostrava a lot of people questioned me but I never questioned myself."
Ethiopian Fantu Magiso upset Kenya's Olympic champion Pamela Jelimo in the women's 800 metres in a national record of one minute 57.56 seconds.
"This is a huge result for me," she said. "I expected that I could run very fast today because my coach told me that today was a good chance for me. This year I am training well and I want to take the chance at the Olympics."
Magiso's team mate Abebe Aregawi also set a national record, clocking a season's best of 3:56.54 in the 1,500 metres.
Kenyan Paul Koech made a spirited attempt to break the men's world steeplechase record, setting the third fastest time ever with a time of 7:54.31.
"I was targeting the world record," Koech said. "During training I had the world record in mind.
"I hoped to achieve the world record here in Rome but I am not disappointed because I achieved a new personal best and now I am confident. I think I am capable of running the world record."
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