Can we change default animation before Update?

I have simple anim tree with a default animation.

At the Start() I want to change my default animation to another one. But it does not work

void Start()
    {
        anim.Play("OneStar_Start");
    }

But if I do it inside the update it does

void Update () {

	    if (Input.GetKeyDown(KeyCode.V))
	    {
            anim.Play("OneStar_Start");
        }
}

Any idea how to get around this? At the beginning I want to start with a different animation other than the default one.

Yes, it is possible. Change Animation.clip to whatever AnimationClip instance you want to make it the default