One of the favourites to lift the Capital One Cup bit the dust at the third-round stage as in-form Everton were beaten 2-1 by Championship side Leeds at Elland Road.
Sloppy passing from Steven Naismith and Seamus Coleman led to Aidy White applying a perfect finish beyond Toffees keeper Jan Mucha with just four minutes gone.
Naismith fluffed a great chance and Victor Anichebe whistled a low drive just away from goal before Nikica Jelavic was sent on as Everton sought a way back into the game, but a Leeds spell of pressure followed and unlike Everton they topped it with a goal.
Rodolph Austin's weaving run was halted by Coleman on the byline and from the subsequent free-kick, El-Hadji Diouf pulled back for Danny Pugh, whose goalbound effort was turned in by Austin with 20 minutes remaining.
Everton managed to scramble a reply when Sylvain Distin headed in with 10 minutes left after some slack marking from Leeds, and thought they had a shot for a penalty when Jason Pearce and Anichebe tussled, but United held on.
Meanwhile, goals from Andrew Halliday, Merouane Zemmama and Richard Smallwood put Middlesbrough through to the fourth round as they beat Preston 3-1 at Deepdale.
North End took Championship scalps Huddersfield and Crystal Palace to reach this stage, but the challenge of an impressive Middlesbrough proved too much as a trio of defensive errors put them out at the third round for the fourth year running.
Both Halliday and Emmanuel Ledesma claimed to have scored Boro's 13th-minute opener, with the Argentine's inswinging corner striking the far post and rolling across - and possibly over - the line before Halliday made sure.
Five minutes later Preston allowed Zemmama far too much time to shoot to the bottom corner from 25 yards, but the hosts pulled one back through Jack King's smart finish on 40 minutes.
Smallwood capped a comfortable win for Boro on 61 minutes, pouncing on the loose ball after Preston defender Paul Huntington headed Zemmama's cross back to Steve Simonsen.