Jesus Christ was enthroned by God the Father, and all powers came under his authority, including the power of Satan and his demons. (Colossians 2)
Paul had written:
in (Christ) all the fullness of Deity dwells in bodily form, and in him you have been made complete, and He is the head over all rule and authority (Colossians 2: 9-10).
But the beautiful thing is, that we have been raised up with Christ and are seated with Him in the heavenly places (Ephesians 2:6).
He has partnered with us to share His victory with us. The word triumphed in (Colossians 2:15), pictures the parade given to a victorious Roman general, Who would bring his spoils and his captives in chains back to Rome and put them on display.
Jesus Christ triumphed over the Devil through His blood. It was the blood of Jesus that paid for our sin and secured for us a place of authority with him in the heavenly places.
That’s why we see the Saints overcoming the Devil by the blood of the Lamb(Revelation 12:11).