If that don't beat all!

if that don't beat all

informal An exclamation of disbelief, as at some surprising, shocking, or amazing occurrence. Well, if that don't beat all! I wasn't expecting to have you here for Christmas!
See also: all, beat, if, that
Farlex Dictionary of Idioms.

If that don't beat all!

 and That beats everything!; Don't that (just) beat all!
Rur. That surpasses everything!; That is amazing!; That takes the cake! (The grammar error, that don't is built into this catchphrase.) Tom: The mayor is kicking the baseball team out of the city. Bill: If that don't beat all! John: Now, here's a funny thing. South America used to be attached to Africa. Fred: That beats everything! John: Yeah.
See also: beat, if, that
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • Are you having a laugh?
  • noes
  • oh noes
  • snap
  • Snap!
  • (oh,) snap
  • hoo-rah
  • get up the yard
  • ah