The Colombians made sure of a 100% record in Group C on Tuesday thanks to a comfortable 4-1 win over Japan in their final game.
Martinez and Colombia will face Uruguay in the second round of the tournament on Saturday.
"We've now got Uruguay in the last 16. It's not going to be easy at all but it's also true that we know each other well. We know what we need to do and how we have to play that match," he told FIFA.com.
Colombia's only previous appearance in the second round of the World Cup was back in 1990.