A late Wilfried Bony goal gave Swansea their first ever win at Old Trafford as they knocked ten-man Manchester United out of the FA Cup with a 2-1 victory.
The away side got off to a fine start with Wayne Routledge opening the scoring after he produced an excellent chipped finish over Anders Lindegaard in goal.
United were level just minutes later, however, through Javier Hernandez who managed to divert Alexander Buttner’s delivery past Gerhard Tremmel.
Swansea gained the advantage in a tight second half after substitute Fabio was shown a red card for a high challenge on Jose Canas, before Bony scored the winner with a thumping header, getting on the end of Wayne Routledge’s cross.
The Swans will meet one of Birmingham City, Bristol Rovers or Crawley Town in the next round, with the latter two’s second-round replay still due to be played.
John Obi Mikel was an unlikely goalscorer to set Chelsea on their way to a 2-0 win at Derby, which featured another diving incident.
The Rams had won 10 and lost just two of their prior 15 games under former England boss Steve McClaren and proved difficult for Jose Mourinho's men to break down at the iPro Stadium.
But Mikel headed in his fourth Chelsea goal on his 300th appearance - his first in this competition since 2007 - after 66 minutes. Oscar doubled the lead five minutes later, rifling home from just inside the penalty area.
Chelsea's 16th successive third-round triumph -- their last loss at this stage was in 1998 against Manchester United -- set up a fourth-round tie at home to Stoke, but was tinged with controversy as Ramires was booked for diving by Andre Marriner.
Much-maligned forward Iago Aspas scored his first Liverpool goal to help his club into the fourth round but it was far from an easy 2-0 victory over Oldham.
Aspas was handed the responsibility of leading the line with 20-goal striker Luis Suarez rested and he eventually delivered with a decent strike 10 minutes after half-time.
James Tarkowski's late own goal, diverting in Raheem Sterling's shot, gave Liverpool the cushion they needed -- especially as they were down to 10 men after Daniel Agger was forced off injured with three substitutions already made.
There was to be no fairytale repeat of Oldham's fourth-round victory over the Reds last January and Liverpool can now look forward to a trip to either Bournemouth or Burton Albion.
In the lunchtime kickoff, Nottingham Forest heaped the pressure on West Ham United manager Sam Allardyce after they knocked their Premier League opponents, who were much understrength, out of the FA Cup following a well-deserved 5-0 victory at the City Ground.
A fine hat trick from Jamie Paterson, a delightful penalty from Djamel Abdoun and a strike from captain Andy Reid piled the misery on West Ham, who were outplayed from start to finish.
There were no such problems from lower league opposition for Sunderland, however, who saw off a spirited Carlisle United 3-1 at the Stadium of Light.
Adam Johnson gave the hosts the lead on 34 minutes, before Matty Robson equalised for Carlisle, currently 16th in League One. But Sunderland proved too strong for their plucky visitors in the second half, with a Sean O'Hanlan own goal and El-Hadj Ba sealing a fourth-round spot, where they will face the winners of the replay between Kidderminster and Peterborough.
Another League One team, Port Vale, were held by Plymouth Argyle in a 2-2 draw at Vale Park.
The home side led 2-0 at the break thanks to goals from Gavin Tomlin and Tom Pope, but Reuben Reid and Ben Purrington ensured a replay will be needed to determine who will host Brighton & Hove Albion in the next round.