Los Cafeteros moved up to six points in Group C with the win to leave them on the brink of qualifying for the last 16 of the World Cup.
"It is, of course, a huge pleasure to see Colombia coming to this level," Pekerman is quoted as saying by BBC Sport.
"First of all, we are at the World Cup after such a long period of time, and then having enjoyed consecutive victories with players who are here for the first time, so they are all very positive situations for us.
"However, we cannot start thinking ahead of time or what might be coming later on."
If Japan fail to beat Greece later tonight Colombia will be through to the next round.