Let's see Jesus as the satan defeater. Inside every saved person is a miniature garden of Eden. There is God in our spirit, us in our soul, and satan in our flesh. Whether we turn our souls to our spirit or to our flesh, determines whether we turn to God or to satan. Day by day the choice between the tree of life (Christ) or the tree of knowledge (man and satan) is set before us, and we must choose of which fruit we wish to eat. The first thing we do when we wake up in the morning, do we turn to Christ ? or do we turn on the news, the finance report (knowledge), or do we complain and argue? Then during the day what are we eating, are we eating life or are we eating knowledge and death?
There is no middle ground. There is not God, Satan, and neutral man in between. Satan dwells in man by proxy from the fall.By default, satan is the father of sinful and fallen man (John 8:44). That is why Jesus said to Peter "get behind me Satan" (Matt 16:23), "you are minding the things of men".
Jesus did not say "Peter you are minding the things of Satan". Of course, Peter was not a devil worshipper or occultist. But what this reveals is that the things of fallen man,is Satan. So fallen man and satan are one, just like renewed and born again man and God are one. This means they are united in thought, purpose and intent.
Of course, Satan is an ex-archangel, and cannot be in more than one place at a time, so "Satan" does not refer to the archangel himself, but wherever his rule and reign may be existing, or wherever satan is expressed through fallen man, is called "Satan". The word satan means adversary, so wherever there is adversary to God, there is satan.
Wherever there is adversary to God, there is satan. Human government, healthcare , education, at the end of the day, is all satan. All these things are exalting man and are opposed to the kingdom of God, therefore they are satan. Satan is only one evil archangel, so how could Satan have a hope to rule the earth? Only by poisoning mankind through the fall, therefore every human being is a potential adversary to God, a potential mini-satan. No good thing dwells in our flesh (Romans 7:18a), and the no good thing is satan.
How to get rid of the satan in our flesh? The only way is for the flesh to die. This is how Jesus defeated satan : by going to the cross, his flesh was killed. We are not free from satan in the flesh until after we die and obtain new resurrected perfect bodies. This is why every Christian person has the capacity to do as much evil as anybody else, as long as satan dwells in the flesh. Satan could so easily cause Judas Iscariot to betray Christ. Sometimes on the news we hear about good Christian folk doing terrible things.
So we could see Jesus as the "satan defeater", by what he did on the cross. Why did Jesus say "get behind me satan"? Because satan in the fallen human flesh, was to follow Jesus to the cross. When Jesus became sin for us on the cross (2 Cor 5:20-21), He became an adversary to God momentarily, that is why the Father left Him. It wasn't just the Son of God who died on the cross but the adversary to God or the principle of satan in every Adamic born human being (the fallen flesh) went to the cross and died. It is by this fact that satan was defeated on the cross, because the flesh which satan used to gain control over mankind and oppose God, died, and even was resurrected.