An under-strength Norwich side were ripped to shreds by the MK Dons as the Premier League side suffered a humiliating 4-0 exit.
The League One visitors were simply far too good for a Norwich side which was completely different to the line-up that drew at Stoke on Sunday, with two goals from former Canary Luke Chadwick setting them on course for victory.
Sam Baldock and substitute Daniel Powell were also on target as Paul Lambert's side simply crumbled.
Shrewsbury dumped Swansea out with a 3-1 win to reach the third round for the first time since 1993.
Graham Turner's men richly deserved their victory, which looked unlikely when Shane Cansdell-Sherriff turned an early header into his own net.
However, Brendan Rodgers's difficult start to life as a top-flight boss continued as the visitors levelled through burly striker Marvin Morgan before Mark Wright put the hosts in front midway through the second half and Nicky Wroe finished Swansea off in the final minute.
QPR saw the euphoria that has greeted Tony Fernandes's takeover of the club pierced when they were dumped out following a 2-0 home defeat to Rochdale.
Jean-Louis Akpa Akpro gave Dale a surprise half-time lead as he slid home a rebound in the fifth minute of a keenly contested first half at Loftus Road.
Gary Jones completed the rout in the second half and booked the League One outfit a place in the third round.
Brighton striker Craig Mackail-Smith's solitary effort sent Sunderland spinning out of the competition with a thumping header five minutes into extra time.
The Seagulls had been unfortunate to have a second-half penalty appeal turned down, when Inigo Calderon tumbled over debut-making Sunderland goalkeeper Keiran Westwood, but Mackail-Smith ensured the newly-promoted npower Championship side went through in any case.
Defeat for Sunderland soured a week already forgettable for their fans following their 1-0 derby defeat to Newcastle at the weekend.
American defender Eric Lichaj made the breakthrough and Villa sealed their victory when substitute Delfouneso popped up with a second goal two minutes from time.
The visitors, who are second bottom in League Two with only one point from four games, had battled hard but Villa's superior class was always evident as they completed a deserved win.
West Brom secured a safe passage into the third round with a 4-1 win against Bournemouth despite manager Roy Hodgson naming an all-changed side at Dean Court.
All 11 players that suffered a late 2-1 defeat at Stamford Bridge were left out of the 18-man squad, with the Baggies manager instead giving a chance to peripheral squad players and youngsters.
While the West Midlanders did not perform with aplomb on the south coast, Hodgson's charges secured a comfortable 4-1 victory without ever exerting too much pressure against the League One side.
The returning Jerome Thomas broke the deadlock with a neat finish in the seventh minute, before Marc-Antoine Fortune extended the visitors' lead with half-time approaching.
Steve Lovell pulled one back for Bournemouth just seconds after the restart, but Simon Cox and Fortune's second of the evening wrapped up the victory.
Mick McCarthy's second-string Wolves strolled to a 4-0 victory in their second-round clash at League Two Northampton.
McCarthy changed all 11 of his players from Saturday's win over Fulham to take on a side 82 league places beneath them - and two goals from Sylvan Ebanks-Blake, Nenad Milijas's classy free-kick and a late Sam Vokes strike vindicated his decision.
Craig Conway inspired Cardiff to a 5-3 extra-time victory over Huddersfield in a thriller.
The Scotland international scored the first goal of extra time before Don Cowie, who had headed a late equaliser from a Conway cross to send the match into an extra period, sealed victory.
Conway had set the tone for a high-scoring contest when he was provider for Cardiff's opening two goals, scored in as many first-half minutes by Gabor Gyepes and Jon Parkin, to give them a 2-0 interval lead.
Huddersfield hit back through Jordan Rhodes and Daniel Ward before the former appeared to have settled the tie with two minutes to play.
But Cowie struck four minutes into injury time to force the extra half-hour - six minutes into which Conway drove at the Terriers' defence and unleashed a 25-yard effort that beat visiting goalkeeper Ian Bennett with the aid of a deflection.
Cowie made sure sure of the win in the 117th minute by thrashing home after Bennett and Gary Naysmith had thwarted efforts from substitute Kenny Miller.
Honduras international Ramon Nunez continued his love affair with the Carling Cup as his brace of wonder strikes saw Leeds through to the third round with a 2-1 victory at Doncaster.
Having scored twice against Bradford in the previous round, the relatively unknown 25-year-old, embarking on his first full season in English football and being given his chance at Leeds after a productive loan spell at Scunthorpe, took his tally for the season to five with a 20-yard special either side of half-time.
Until the intervention of the former Chivas winger, James Hayter's early goal had looked set to give Doncaster a first home win over Leeds in 60 years but, after Nunez had taken effect, the home side were forced to return their thoughts to a league campaign that has failed to produce a point so far.
League One high-flyers Charlton pulled off a shock with a 2-1 victory over Championship side Reading at The Valley.
Paul Benson and Jason Euell scored either side of the break, although the hosts had to hold on for their upset win as Sean Morrison pulled a goal back before Mathieu Manset saw a shot cleared off the line.
Ruben Bover Izquierdo hit the woodwork late on after a mazy run for the Addicks but it mattered not as they celebrated their progress.
Goalkeeper Scott Bevan saved two spot-kicks as Bristol Rovers earned a second-round tie at Leyton Orient with victory in a penalty shoot-out over Watford after the game had finished 1-1.
John Eustace and Carl Dickinson were the Watford players denied and, although Scott McGleish shot wide for Rovers, they won the shootout 4-2 with the final kick not taken.
Both of the goals in 120 minutes of highly competitive cup-tie action came in the opening five minutes.
Marvin Sordell slid in to convert a low cross from Craig Forsyth just two minutes in and three minutes later Matt Harrold equalised with a superbly-struck shot on the turn from 25 yards.
Both sides had chances to win before the shootout which was completed by the coolest of spot-kicks from Rovers' substitute Mustapha Carayol.
Jo Kuffour, Adam Virgo, and Wayne Brown also scored for Rovers in the shootout, while Sordell and Adrian Mariappa netted for Watford.
Burnley captain Chris McCann came to his side's rescue with an extra-time winner to repel a spirited fightback by Barnet as they won their second-round tie 3-2 at Turf Moor.
Substitute McCann fired home in the 105th minute from a Brian Easton cross to save the Championship side's blushes after the League Two team's dramatic late revival had forced the extra half-hour.
Jay Rodriguez opened the scoring for Burnley in the 38th minute when he deflected home a Trippier cross before Wade Elliott fired them 2-0 ahead in the 64th minute and it seemed like the visitors' brave resistance had finally crumbled.
But Barnet hit back with veteran striker Steve Kabba, on as a 73rd-minute replacement for Price, sliding in at the far post to reduce the deficit from a Mark Marshall cross - and they forced extra time in dramatic fashion when another substitute, Ricky Holmes, prodded home the equaliser in the fourth minute of stoppage time.
Burnley finally settled in the extra period with McCann - on at the end of normal time for Keith Treacy - nudging them back in front before Trippier, Zavon Hines and Ross Wallace all missed chances to make it four.
Millwall's Championship class told as first-half goals from Hamer Bouazza and Tamika Mkandawire secured a comfortable 2-0 win over Morecambe in the second round.
The League Two visitors had dumped Barnsley out in the previous round in a 2-0 success at Oakwell but there was to be no upset at the New Den.
Bouazza opened the scoring in the 34th minute with a superb free-kick and Mkandawire added a second on the stroke of half-time with another fine finish.
Sven Goran Eriksson avoided a potential Carling Cup embarrassment after his Leicester side came from behind to beat Bury 4-2.
The former England boss made 10 changes to his team and almost paid the price, Mike Jones and Peter Sweeney putting the hosts 2-1 up after Jeff Schlupp's opener.
Paul Gallagher equalised to settle nerves before Lloyd Dyer and Neil Danns completed the comeback.
Nottingham Forest cruised into the third round with an impressive performance in a 4-1 win against Wycombe.
Steve McClaren's team controlled the game from start to finish and led 2-0 at the break through early strikes by Ishmael Miller and a penalty from the impressive Lewis McGugan.
The Championship outfit did not relent in the second half and further goals from Robbie Findley and Radoslaw Majewski sealed a comfortable night, with Elliot Benyon's spot-kick a mere consolation for the hosts.
Wilfried Zaha scored a brace as Crystal Palace defeated Crawley 2-0 in their rescheduled first-round clash at Selhurst Park.
The striker netted after 54 minutes before adding a second four minutes later to send the Championship side into the second round for the fourth year running, where they face a home tie against Wigan.