“I think it's important to remember that Yohan Blake and Usain Bolt are both 100m runners - I'm a 400m runner running in a different event”
"He ran a personal best in May of 11.4 seconds and now he's run 10.8," Pistorius told BBC Sport.
"You just don't see increments that big. I'm very, very surprised. I think he's going to do a phenomenal job."
Peacock, 19 and from Cambridge, set a world record for single-leg amputees with a time of 10.85secs when he ran as a guest at the US Paralympic trials in June.
"I've been hugely surprised," Pistorius added. "I've never seen anybody improve more than half a second in three or four months.
"In front of his home country I know the guys will be supporting him more than ever, and good for him. He should run a phenomenal race."
Pistorius returns to London just three weeks after his groundbreaking appearance at the Olympic Games, in which he made the 400m semi-final and anchored the South African quartet in the 4x400m relay final.
The 25-year-old faces a punishing schedule at the Paralympics as he competes in four events - the 100m, 200m, 400m and 4x100m relay - and admits that his focus on the 400m has affected his shorter sprints.
Despite that, his 100m final remains the closest the Paralympic Games comes to matching the excitement of the Olympic sprint showdowns between Jamaicans Usain Bolt and Yohan Blake.
Peacock aims to make impact
"I think it's important to remember that Yohan Blake and Usain Bolt are both 100m runners - I'm a 400m runner running in a different event," said Pistorius.
"I've run maybe two races in the last two years. I'd say the top three guys would probably be Arnu Fourie, Blake Leeper and Jonnie Peacock for that event, so if I can just finish in the top three I'll be happy.
"Although it inspires me to push myself harder I'm not going to start focusing on the 100 - it's just not my event.
"I'm a 400m athlete and although I'm the current defending Paralympic champion and I'd really like to try to maintain my [100m] title, it is definitely going to be extremely difficult."
Pistorius said he is "humbled" by the prospect of carrying the South African flag at Wednesday's opening ceremony and expects the London Games to be a landmark for Paralympic sport.
"I think people's perceptions have changed quite a lot in the UK," he said, "and by hosting the Paralympic Games here, a lot of international media will take this message to their countries who may not share the same level of education when it comes to disability as the UK.
"Through that message, they'll view Paralympic sport through the eyes of Great Britain.
"I just think it's going to be one of those things that's going to change a lot of people's perceptions around the world when it comes to Paralympic sport and people living with disabilities."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.