"It (the start) was horrifying for me. I think it is just race rust and I just need to get a few races in," said Bolt who holds the world records in the 100 and 200m. (Agencies)
"The rounds in the world championships will help that and get my legs freer and a bit lighter. Hopefully the coach will figure out what I need to do to get me more explosive out of the blocks, I guess," Bolt said.
American Michael Rodgers was second in 9.98, and Jamaica's Nesta Carter was third. Kim Collins of Saint Kitts and Nevis faded to finish fourth after a fantastic start.
"For the first time, I think, in a long while I was slightly nervous. Initially, I was excited to come out because I knew it was going to be a big crowd," said Bolt.
"But when I got out there and I saw that it was jam-packed and the energy was still like the Olympics, it was just wonderful, so I was slightly nervous but I loved the energy of the crowd," he added.
In the 200, Warren Weir of Jamaica, who won bronze a year ago, edged compatriot Jason Young by 0.1 to win in 19.89. Wallace Spearmon of the US was third in 20.18. And, Olympic champion Kirani James of Grenada comfortably won the 400m in 44.65, beating Tony McQuay and Jonathan Borlee.
"It (the start) was horrifying for me. I think it is just race rust and I just need to get a few races in," said Bolt who holds the world records in the 100 and 200m.