"Once Upon a Time in Mexico" Song I.D....

[Carcharodon]

So I'm trying to find the name of the song Banderas plays at the beginning of Once Upon a Time in Mexico, when he's testing a guitar for the old guitar maker. I've heard it in the movie and elsewhere, but I'll be damned if I can identify it by name, or find it. I LOVE that song, especially the way it is presented in the movie itself.

Anybody know what I'm talking about?

 

[PyroChamber]

I think it's called "El Mariachi" and it's done by Robert Rodriguez himself