Swansea gave an instant debut to Conor Hourihane, as they strolled to a 5-1 victory over Championship rivals Nottingham Forest to progress to the fifth round of the FA Cup
The Republic of Ireland midfielder was signed on loan from Aston Villa until the end of the season. Another Irish international Ryan Manning also lined out for the Swans, and he was involved in setting up goal number for the hosts
Doubles from Matt Grimes and Liam Cullen, as well as Oli Cooper's first senior goal, sent Swansea into the last 16 of the competition for the third time in four seasons.
Anthony Knockaert gave Forest hope at 2-1 at the start of the second half, and they will no doubt question the legitimacy of Swansea's third goal from the penalty spot.
But Swansea showed the form which has taken them to second spot in the Championship in extending their unbeaten home run at the Liberty Stadium to 10 games.
West Ham cruised into the next round with a routine 4-0 home win over Doncaster.
First-half goals from Pablo Fornals and Andriy Yarmolenko put David Moyes' side in control and after Andy Butler put through his own net, debutant Oladapo Afolayan added the cherry on top with a late fourth.
The win sets up a last-16 meeting with one of Manchester United or Liverpool for the Hammers, who have now won their last five matches.
Moyes made eight changes from the victory against West Brom with midweek matchwinner Michail Antonio and the only forward at the club one of several to drop to the bench.
Sheffield United secured just their third win of the season as fans' favourite Billy Sharp helped Chris Wilder's men avoid an FA Cup upset against Plymouth.
The Blades have endured a wretched campaign but the Premier League's bottom side have shown flickers of life recently, making it three wins from four matches in all competitions.
Veteran striker Sharp was the key man at Bramall Lane, providing a lovely cross for Chris Basham's opener before scoring a fine goal early in the second half of a 2-1 fourth-round win against League One side Plymouth.
Callum Styles fired a deserved winner as Barnsley beat Norwich 1-0 to reach round five for the first time in eight years.
Man-of-the-match Styles struck the decisive goal early in the second half as the Reds gained revenge for their narrow defeat to the Sky Bet Championship leaders earlier this month.
Victory for Barnsley sets up a potential home tie against Chelsea, who the South Yorkshire side famously beat at Oakwell in 2008 to reach the semi-finals.
Yves Bissouma's stunning strike helped Brighton avoid a cup upset as they marched on with a 2-1 win over League One Blackpool.
A dominant second-half performance eased Bristol City past Millwall at The Den, with a 3-0 win securing their place in the fifth round for just the second time in 20 years.
The visitors took the lead against the run of play through a Famara Diedhiou penalty and despite creating a number of opportunities, Millwall were unable to get the better of Max O'Leary in the Bristol City goal.
The all-Championship encounter was effectively settled by a deflected Nahki Wells free-kick just before the hour mark, before Antoine Semenyo capped a thoroughly professional performance from Dean Holden's side.