Leeds impressed in the first half but substitute Calum Chambers put Arsenal ahead with a header from a corner in the 55th minute, netting with his first touch of the game and 23 seconds after his introduction for the injured Ben White.
After a header from captain Liam Cooper to goalkeeper Illan Meslier fell short, former Whites loanee Eddie Nketiah then doubled Arsenal's lead in the 69th minute.
Graham Smyth, the YEP's chief football writer, hands out the scores as Leeds squandered an opportunity to book a place in the quarter-finals.
7. Adam Forshaw
5 - Struggled against pace, was turned too easily at times. Leeds' control came more from Phillips and Llorente. Photo by Julian Finney/Getty Images.
8. Dan James
5 - His pace troubled Arsenal but the final ball let him down. Disappeared from the game as an influence after the break. Photo by Julian Finney/Getty Images.
9. Jack Harrison
6 - Carried a threat in the first half. Less so in the second half but was willing and tried to get on the ball. Picture by Bruce Rollinson.
10. Tyler Roberts
4 - A couple of nice moments aside, didn't take his chance again. Little surprise to see him withdrawn. Photo by JUSTIN TALLIS/AFP via Getty Images.
11. Rodrigo
6 - Some nice first half moments. Adventurous but not entirely accurate. Lacked service and impact in the second half. Picture by Bruce Rollinson.
12. Mateusz Klich (sub)
5 - No real impact or control. Lots of running without being able to link defence and attack. Picture by Bruce Rollinson.