Viktor was clearly caught-off guard/surprised by Michael's speed. It was the first time he had ever fought anyone that fast. But, it was crystal clear to me that Viktor adapted and started to use the same level of speed Michael was using.
Also, don't know why people think that Viktor blitzing that peasant in RotL does not count as super speed when he literally moved so fast that no one could see him moving. He was moving his whole body too not just his arms and it's not like the distance was only a few feet. It was much longer distance than that.