Meaning:
Literally translated as “to beat magic with magic,” this line first appeared in the comical kungfu animation series titled “Jackie Chan Adventures” that ran between the years of 2000 and 2005 on Kids WB TV. In one episode, Chan’s uncle who calls himself “Old Daddy” asked after beating some bad guys: “What takeaways can you get from this fight?” And all the others answered in a united voice: “We must beat magic with magic,” meaning that they should employ the same tactics used by their enemies to fight against them.
Example:
A: 小胖最近欺负小明了吗？
Xiǎopàng zuìjìn qīfù xiǎomíng le ma？
Did Xiaopang bully Xiaoming again recently?
B: 没有，自从小明让他上中学的哥哥教训了小胖一次以后，小胖就不再找小明的麻烦了。
Méiyǒu， zìcóng xiǎomíng ràng tā shàng zhōngxué de gēge jiàoxùn le xiǎopàng yīcì yǐhòu，xiǎopàng jiù búzài zhǎo xiǎomíng de máfán le。
No. He left Xiaoming alone after being taught a lesson by Xiaoming’s elder brother who’s in middle school.
A: 原来小明用魔法打败魔法了。
Yuánlái xiǎomíng yòng mófǎ dǎbài mófǎ le。
It sounds like Xiaoming solved the problem with an eye for an eye.