He fled before him; being surprised by the unexpected coming of Abimelech, and possibly not fully prepared for the encounter. Many were overthrown and wounded, being pursued and overtaken by Abimelech.
Related Commentaries of Judges 9:40
Judges 9:40
40 And Abimelech chased him, and he fled before him, and many were overthrown and wounded, even unto the entering of the gate.