Alejandro was a really big hit in Europe. It was #1 in 6 countries, #2 in 5, #3 in 6, #4 in 5, #5 in 2, #7 in 1 and #11 in 1. AND it went 3xPlatinum in Russia, selling double Poker Face and Bad Romance combined...
I remember also hearing that Alejandro sparked interest in a lot of Latin countries that weren't really there for her before. I'm only comparing it to a U.S standard. Singles work differently in different countries. Also I do believe there's a correlation between album sales/singles unless you're the biggest thing around. It's weird when you think about it eh? XD Gaga is like the big cheese of the industry but it's harder for her to get her singles airplay and sometimes sold when it's a later single.