An expression - Can't figure it out

What does the expression "go toe to toe", mean?




As an example:

x: "I am 63...three years older than that young punk ---insert name----"




y: "Any chance of seeing you two go toe to toe?"

 

I hear there used to be an old variation of boxing where each contestant had to keep one toe on a line drawn between them. It kept them at close range and made it particularly brutal. Yo Adriaaaaaaaaannnnn