The Spain international got clear of his marker before powerfully heading in a Toni Kroos corner at the Santiago Bernabeu.
It marked Ramos' second goal in as many games for Madrid, but former Argentina and Barca midfielder Riquelme believes he would have less luck in South America.
"In South America, they mark in a different way," the Boca Juniors great told Canal 13.
"They wouldn't let Sergio Ramos start, he wouldn't score a goal."
Ramos has scored 10 goals in all competitions for Madrid this season, the first time he has reached double figures in his career.