The 22-year-old was brought on at half time in Los Cafeteros' Group C clash, registering an assist and a goal to cap a fine individual performance.
It follows impressive displays from the Monaco star in Colombia's opening two group games against Ivory Coast and Japan, but Pekerman says that more can be expected from Rodriguez.
"I think what James Rodriguez has done today simply demonstrates what we expected from him," Pekerman is quoted as saying by BBC Sport.
"From the beginning of this World Cup, he has shown that he is very well physically, is fit and that we can expect a lot from him."
The victory ensured that Colombia topped their group, setting up a last-16 meeting with Uruguay on Saturday night.