What is the specific term for this (please read details)

In an argument, what is the term for when one person focuses on a totally non-relevant detail in order to either shut down their opponent or bring all attention to themself? For example, Party A might say “Last Tuesday you promised that This Thing would happen, but you completely misled me and instead you did That Thing, which caused much distress.” and Party B responds “It wasn’t Tuesday, it was Monday, I know this because I had just eaten lunch with my friend at Restaurant. You’re completely wrong when you say Tuesday, on Tuesday I was at home washing my cat…blah blah blah” thus diverting the discussion from the point.
I know there is a real term for this, not just “going off track” or “derailing” or some such. Does any body know it?
Thank you.