"Εγώ είμαι πίσω σου."

Translation: I am behind you.

[LewieHayes]

That made me look...

[jayfender]

Does this also mean "I support you" or is it only referring to physical position?

[G.Georgopoulos]

It's about physical position only.

Είμαι δίπλα σου=I'm by your side=I support you (so, 2 in 1)

[jayfender]

Ευχαριστώ σας!

[G.Georgopoulos]

"Σε/Σας ευχαριστώ" ;)

[Majid.Behrang]

Handy when trying to reserve your place in a queue, while being to busy/lazy to stand in it.