He was afraid of Lucian because he was the perfect Lycan, able to change at will, and any mindless lycan was his to control. Before that, he was afraid of him because he knew lycans were bad ass, he remembered what William did to his ranks.
And yes, Viktor is powerful, that was Raze he killed, the black one, and one of the oldest lycans besides Lucian.
Now the only reason Viktor was beatin Micheal is because it was Micheal's 1st time as a Hybrid, he was also extremely inexperienced in combat, since he's only 20-something, and he was training to be a nurse. If you look at the fight, Micheal is so fast Viktor can't keep up at first, but once his inexperience shows, Viktor capitalizes on it.