I need an animation not to loop and appear only once, followed by an animation that will loop

I’ve got an animation in a clip. I want the first part, 50 frames or so, be triggered only once and I don’t want it to loop, followed by the second part, which should loop forever once the play has reached it frame 51 approx. for the first time.

I had a problem with WrapMode in unity 4.6.7f1. The solution was to click on the animation clip file in Unity. Then toggle the loop flag. This would make it loop or stop.