Garry Monk took full responsibility for Leeds United's exit from the FA Cup at the hands of non-league Sutton United.
Sutton captain Jamie Collins scored the winner from the penalty spot as the National League side stunned a team 83 places above them.
In total, Monk made 10 changes from his promotion-chasing side's midweek win over Nottingham Forest, handing debuts to academy products Paul McKay and Billy Whitehouse.
The likes of Robert Green, Pablo Hernandez and top-scorer Chris Wood were left out of the match-day squad, and after the chastening defeat, Monk admitted: "I made a lot of changes and it backfired. I take full responsibility."
Sutton manager Paul Doswell said: "I would have done exactly the same as Garry. The riches of the Premier League mean it's a no brainer for him. I can't praise the players enough. Every time they've been asked a question they have responded."
Roarie Deacon had a goal harshly disallowed after five minutes and the winger, whose five goals in the competition had fired Sutton this far, continued to torment the Sky Bet Championship side for the rest of the first half.
Sutton got the breakthrough they deserved six minutes into the second half, thanks to some shambolic Leeds defending.
Goalkeeper Marco Silvestri came out to meet Maxime Biamou but succeeded only in colliding with team-mate Lewie Coyle, taking the Sutton forward out and giving referee Stuart Attwell little option but to point to the spot.
Collins, a builder by trade, stepped up and nervelessly sent Silvestri the wrong way to spark wild celebrations on the old-style terraces behind the goal.
Leeds were reduced to 10 men with 10 minutes left when captain Liam Cooper was sent off.