furtwaengler, Derek, and m1469: thank you for listening.
Unfortunately I am not familiar with Mahler's setting, so I went to look it up.

Didn't expect that! There is a surprising resemblance with the opening motif I chose. My intentions for the beginning of my piece were to gradually reveal the tonality of Eb major, thus the open 5th that seems to float around for a while.
I should listen to more Mahler. Thanks for pointing that out furtwaengler, it was a pleasant surprise.