Watford suffered an embarrassing League Cup exit as Championship side Bristol City beat the Premier League club 3-2 in the second round on Tuesday.
Marco Silva's side were the only top-flight outfit to perish on a night when clubs showed their disdain for the competition by making 274 team changes across the 19 ties.
Etienne Capoue put Watford ahead from Will Hughes' 47th-minute cross, only for Freddy Hinds to equalise from 30 yards 12 minutes later.
Bobby Reid handed City a shock lead in the 67th minute and Watford were in deeper trouble when Jose Holebas was sent off in the 88th minute for a second bookable offence.
Niclas Eliasson made City's advantage pay with the killer third in stoppage time before Adrian Mariappa hit an irrelevant reply for Watford.
Bristol City assistant boss Dean Holden said: "We've got competition for places and we challenged the players coming into the squad to take that chance. They did that."
Frank de Boer got his first win as Crystal Palace manager as James McArthur's double sealed a 2-1 win over second-tier Ipswich Town at Selhurst Park.
After scoreless Premier League defeats against Huddersfield Town and Liverpool, Palace's first goal under De Boer finally arrived when McArthur slotted home in the 76th minute.
Scottish midfielder McArthur scored again eight minutes later and Bersant Celina's 90th-minute reply for Ipswich couldn't stop De Boer going home happy at last.
"You're always waiting for that moment (the first goal), so I'm very pleased for the fans," De Boer said.
"A lot of players showed that they are ready, so for that spirit I am pleased."
West Bromwich Albion eased to a 3-1 win at fourth-tier Accrington Stanley as Salomon Rondon, Matt Phillips and Jay Rodriguez netted for the Premier League side.
Bournemouth came from behind to win 2-1 at second-tier Birmingham City, ruining Blues boss Harry Redknapp's hopes of upsetting the club where he spent nine years at the start of his coaching career.
On-loan Chelsea striker Tammy Abraham hit his first goal for Swansea City in a 4-1 win over third-tier Milton Keynes Dons.
Ryan Seager put the Dons ahead in the 17th minute, but Leroy Fer's double was followed by Abraham's 71st-minute tap-in and Jordan Ayew's 86th-minute strike.
Islam Slimani bagged a brace as Leicester City cruised to a 4-1 win at second-tier Sheffield United.
Demarai Gray's fine solo goal opened the scoring in the 52nd minute, then, after members of the West Indies cricket team were introduced to the crowd at the interval, United were bowled over as Slimani netted in the 63rd and 67th minutes.
Caolan Lavery's 83rd-minute reply for United was followed by Ahmed Musa's stoppage-time fourth for Leicester.
James Tilley, 19, came off the bench to give Brighton and Hove Albion a 1-0 win against fourth-tier Barnet with his first senior goal in the 54th minute.
Holders Manchester United, along with Chelsea, Arsenal, Liverpool, Tottenham Hotspur and Manchester City, will enter the competition in the third round, with the draw to be held in Beijing on Thursday.
For more sports coverage, visit the ABS-CBN Sports website.