The 30-year-old Jamaican overcame an aweful start on Friday to win heat 6 in 10.07 seconds. The top three finisher in each heat automatically qualify for the semifinals, Xinhua news agency reported.
Bolt, who has won 19 world and Olympic gold medals, was not happy with his performance and said the blocks had affected his race.
“That was very bad, I stumbled coming out of the blocks. I’m not very fond of these blocks. I think these are the worst ones I’ve ever experienced. I have to get this start together because I can’t keep doing this.
“It’s shaky. When I did my warm up it pushed back. It is just not what I am used to. Not as sturdy or firm.”
Bolt, who holds a world record of 9.58 seconds, was welcomed by a boisterous crowd of 70,000 at the Olympic Stadium, where he won three Olympic gold medals five years ago.
“The crowd is always wonderful,” he said. “They always show me so much love and I always appreciate being here. I’m excited about getting through to that final and doing my job to my best.
“I had to work hard but I’m actually glad I had to push myself more to blow the cobwebs away. I’m feeling ok but it wasn’t a great race.
“The people gave me a lot of appreciation as normal but the only different thing is there were loads of Jamaicans in the crowd which I’m happy about – I just want to make them proud.”
China’s Sun Bingtian won heat 4 with a season best time of 10.03 seconds and his compatriot Xie Zhenye also reached the semifinals by finishing third in 10.13 in the first group, behind Japan’s Abdul Hakim Sani Brown and Jamaica’s Yohan Blake.
Bolt was all praise for the Asian atheltes, saying, “The guys (from Asia) are always going to come out and run fast. They are all stepping up this season which is great. I’m excited to see what they can do in these championships.”
He confirmed his decision to call it quits after the 4x100m relay in London.
“My dad wants me to go on but I am happy to retire after the championships.”