knock spots off someone/something
knock (the) spots off (someone or something)
To completely outclass, outdo, or outperform someone or something; to soundly defeat or best someone or something. Primarily heard in UK, Australia. Wow, this coffee knocks the spots off the stuff we get back home. Catherine knocked spots off the other kids in the spelling bee.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
knock spots off someone/somethingBRITISH, INFORMAL
If one thing or person knocks spots off another, the first is much better than the second. I'm looking forward to the return of her chat show. It knocks spots off all the others. Caroline didn't have much experience, but she knocked spots off everyone else I'd interviewed — she was so charming and friendly. Note: The reference here is probably to someone who is shooting so well that they are able to knock out the spots or marks on a playing card that they are aiming at.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012