Initial sprite rotation for velocity direction

I set up my sprite to face right initially, then use this code so that it faces the correct direction every time. (code modified from someone's answer here):

 public void FaceVelocityDirection()
     {
         _rb2D.angularVelocity = 0;
 
         Vector2 _dir = _rb2D.velocity;
         float angle = Mathf.Atan2(_dir.y, _dir.x) * Mathf.Rad2Deg;
         transform.rotation = Quaternion.AngleAxis(angle, Vector3.forward);
     }

Then I use this code to fire it up:

 public void FireForward ()
     {
         _rb2D.AddForce (transform.up * 100 * _speed);
     }

When I'm firing up, it is visibly seen at least one frame that the sprite faces the right direction, then after one frame update it rotates up. I place it in update and it can still be seen. Any advice on how to fix this?