The Briton has struggled with injury over the past 18 months and missed the 2015 Doha World Championships.
He returned to form by setting the world's best time this year - 10.68 seconds - in July, but says Jarryd Wallace is the leading contender.
"In my eyes he's the one to beat," Peacock, 23, told BBC Sport.
"I went into London 2012 as clear fastest; it's a very a different pressure this time, but I'm more relaxed."
The final of the Games' blue riband event is held on Friday night (23:59) and is stacked with talented sprinters despite the loss of USA's multiple world champion Richard Browne to injury, and the absence of Oscar Pistorius, who is serving six years in jail for killing girlfriend Reeva Steenkamp.
Aside from American Wallace, who has run 10.71, German Felix Streng (10.89) and Amu Fourie of South Africa (11.00) have also performed well this season.
Brazil's Paralympic pin-up Alan Fonteles Oliveira is also being backed by some to recapture the form which saw him become a triple world champion in 2013.
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"The sport has moved on hugely in the last four years, it's evolving and people seem to be getting faster," said Peacock.
"There were two people sub-11 seconds in 2012 and now there's at least six the last year so it'll definitely be a different experience to London."
Peacock's injury struggles were caused by problems with the connection between the stump in his amputated right leg and the carbon fibre blade.
After taking time out to heal, and adapt his running technique, the sprinter says he is ready to produce his best form.
"I took so much confidence and experience from 2012 which was so special, but I then had some losses in 2014 and missing the Worlds in 2015 was really difficult.
"But that taught me quite a lot about myself and I know how to deal with the pressure now."
ParalympicsGB have been set a target of 121 medals, one more than they secured at London 2012.
Peacock believes the squad can take confidence from the achievements of Team GB, who won two more Olympic medals in Rio than at London 2012.
"GB winning so many Olympic medals was great and watching someone like [cyclist] Jason Kenny really stuck with me," he said.
"It made me really remember the importance of the confidence factor; knowing what you're capable of and knowing you can win which is something we'll all draw on."
Peacock also feels that, despite a slow start to ticket sales and concerns about budget cuts by the organising committee, the event will be a success.
"Come the day the Games open, people will be really surprised," he said. "When they see the performances of British athletes, going out getting gold medals it will all be forgotten about.
"The Paralympics nailed it for Britain in 2012 and what I want now is for 2016 to nail the Americas.
"I want the people of South America to see what Paralympic sport is about - it's true sport and there are some real great performers out there."
London Paralympic champion Jonnie Peacock insists he is not the favourite for the T44 100m crown in Rio, despite being ranked world number one.