50 move rule-- Automatic?

I was just playing a blitz game. I was a bit short on time and we ended up king & rook aside. My opponent didn't agree to a draw (in an attempt to flag or in hopes I'd hang my rook in time trouble), so we played on. Some folks would be mad, but I'd probably do the same for a bit if my opponent was out of time. After several permutations of rook back and forth with a king move mixed in to prevent 3-fold the game was called due to 50 move. I was hitting the draw button every move in hopes of hitting a 3-fold, so I don't know if the draw button triggered it or if it was automatic.

50-move is not automtic and must be claimed. 

Then hitting the button was the right thing- Thanks!