The Bible tells us that Jesus came down to Earth in order that He would destroy the works of the devil. That means He came to Earth, died on the cross, and rose from the dead in order to destroy the power of darkness. That also means that darkness has been defeated.
If that's the case then the battle we are fighting isn't to gain victory but from a place of victory. Our fight is to remind ourselves and the powers of darkness that Jesus has already won and so have we! God does not need you to defeat the devil because Jesus has already done that. He has given us the victory banner to wave above our heads. Colossians 2:13-15 says:
'You were dead because of your sins and because your sinful nature was not yet cut away. Then God made you alive with Christ, for he forgave all our sins. He canceled the record of the charges against us and took it away by nailing it to the cross. In this way, he disarmed the spiritual rulers and authorities. He shamed them publicly by his victory over them on the cross.' Colossians 2:13-15
The cross was the place where the prince of this world, Satan, lost at his own game. Satan had intended to use Jesus' horrible death to destroy God's work. Instead, God used Jesus' death on the cross to be the sacrifice for our sins. Through the resurrection of Jesus, God took away the power of sin and death. In an incredible act of love on the cross, God removed Satan's ability to accuse us. He defeated the death penalty of sin for us, and brought to us a way of life, joy and beauty. Our victory has been won and our enemies have been defeated. Forever.
In Christ, you fight from victory, not for victory.