take somebody/something to the mat
take (someone) to the mat
To confront or argue with someone (about some issue). An allusion to the sport of wrestling, in which competitors try to grapple each other onto a mat to pin them or make them submit. The senator took the president to the mat about the tax plan's negative impact on working-class citizens.
take somebody/something to the ˈmat(American English, informal) to get involved in an argument with somebody/something: He took them to the mat on that issue.
Both of these idioms come from the sport of wrestling, in which two people fight by holding each other and trying to force the other person to the ground or mat.