Manchester United will host Liverpool in an FA Cup quarter-final blockbuster after the bitter rivals took contrasting routes to their fifth round victories on Wednesday.

United eased the pressure on beleaguered boss Erik ten Hag as they scraped through with a 1-0 win at Nottingham Forest thanks to Casemiro's late goal.

Fresh from their League Cup final triumph against Chelsea on Sunday, Liverpool relied on their youngsters again in a 3-0 win against second tier Southampton at Anfield.

With Liverpool ravaged by injuries to Mohamed Salah, Darwin Nunez, Diogo Jota and Alisson Becker among others, Lewis Koumas marked his debut with the opening goal in the 44th minute.

Jayden Danns, another 18-year-old, netted Liverpool's second in the 73rd minute with a composed finish that belied his tender age.

Danns capped the victory in the 88th minute when he lashed home in front of The Kop.

At the City Ground, United reached the FA Cup quarter-finals for a record 48th time.

The FA Cup represents United's last silverware chance this term and, after missing a host of chances, they finally hit the target in the 89th minute when Bruno Fernandes' free-kick was headed in by Casemiro.

At Stamford Bridge, Mauricio Pochettino will have felt similar relief to Ten Hag.

With the pressure mounting in his troubled first season in charge, the Argentine was indebted to Conor Gallagher for a late winner in a 3-2 win against Championship promotion chasers Leeds.

Mateo Joseph put Leeds ahead before Nicolas Jackson and Mykhailo Mudryk netted to give Chelsea the lead.

Joseph scored again but Gallagher won it in the 90th minute.

Elsewhere, Wolves beat Brighton 1-0 at Molineux, with Mario Lemina's goal after just 77 seconds securing a home tie against second tier Coventry.

Holders Manchester City, who beat Luton 6-2 on Tuesday, will host Newcastle in the other quarter-final. (AFP)