From the standpoint of eternity, the victory over Satan was won by Jesus two thousand years ago at Calvary.

The spiritual battles over the last two thousand years will come together in a great victory of Jesus Christ at the Battle of Armageddon.

The final judgment of this world and the defeat of Satan, the prince of this world, was made sure when Jesus spoke the words,
          "It is fininshed."

The Bible tells us that at the very moment of Christ's apparent defeat on the cross He won the battle for the earth and the souls of man.

"Now is the judgment of this world; now the ruler of this world will be cast out. And I, if I am lifted up from the earth, will draw all peoples to Myself"  John 12:31-32

Jesus promised that the war for the planet earth will end with His total victory over evil when He returns to setup His Kingdom.

But the prophets warn that the Antichrist and Satan will unleash spiritual warfare against the tribulation saints during the Great Tribulation