Green’s Dictionary of Slang

(Aus./US) to have someone at a disadvantage; to feel superior towards.

1908		N.Y. Times 30 Sept. in Fleming Unforgettable Season (1981) 269: They say [...] his name has got it on the Goldbrick twins for being a household word.
1909		Van Loan ‘The Fresh Guy’ in Big League (2004) 27: He’s got it on you, Catten, and you’re the best in the big league.
1910		B. Fisher Mutt & Jeff 25 Feb. [synd. cartoon] I want to get a peep at the kink of Spain so that I’ll have it on my friend Jeff.
1920		F.S. Fitzgerald This Side of Paradise in Bodley Head Scott Fitzgerald III (1960) 53: We came to Princeton so we could feel that way toward the small colleges — have it on ’em, more self-confidence, dress better, cut a swathe.
1928		M. West Pleasure Man (1997) II ii: No, you won’t beat my head off because I’ve got it on you.
1953		K. Tennant Joyful Condemned 49: You needn’t say anything [...] We’ve got it on you. Your cobber’s come his guts.
1981		A. Weller Day of the Dog 84: ‘She can’t fight.’ ‘Can she what! [...] She ’ad it all over Jenny Campton.’.