Revenge in the air in FA Cup blockbusters
Manchester City's Sergio Aguero (R) celebrates scoring his second goal during their English FA Cup fourth round match, against Watford, at the Etihad Stadium in Manchester, on January 25, 2014 - by Paul Ellis
A lack of major head-to-head clashes and true upsets means that this season's FA Cup has yet to capture the imagination, but that could change in round five as four of the country's biggest teams prepare to face off.
Manchester City host Premier League title rivals Chelsea on Saturday, with Arsenal tackling Liverpool a day later, and both ties carry extra intrigue due to recent encounters between their respective protagonists.
Chelsea took control of the title race with a 1-0 victory at City on February 3, while Arsenal's own championship ambitions were ruthlessly undermined in a chastening 5-1 defeat at Anfield last weekend.
Liverpool's 3-2 win at Fulham on Wednesday means that just four points now separate the four teams at the head of the table, with Chelsea leading the way and the club from Merseyside bringing up the rear.
Liverpool's victory over Arsenal may have left deep scars, with the London club's manager Arsene Wenger admitting after a 0-0 draw with Manchester United on Wednesday that his players had become "nervous".
Wenger saw his side's defence breached four times in the first 20 minutes at Anfield, but Arsenal goalkeeper Wojciech Szczesny believes there is no chance of a repeat at the Emirates Stadium on Sunday.
"You can't say you saw the real Arsenal at Anfield. You have to judge us over a longer period of time," said the Poland international.
"People have seen the real Arsenal over the last year. We conceded five on Saturday, but our defensive record over the last year or so has been amazing.
"You saw that against United. We didn't concede against a top side with fantastic strikers, and we hope to do that against Liverpool."
Liverpool captain Steven Gerrard has warned his team-mates that Arsenal will not display the same generosity when the teams resume hostilities.
"Top sides, when they get beat 5-1, they are hurt," said the England midfielder, who gave his side victory at Fulham with a nerveless injury-time penalty.
"We're expecting a tight game at the Emirates and I think the 5-1 game will have no bearing on this game coming. We're expecting a really tough game."
City had an unwanted night off on Wednesday after their home match with future League Cup final opponents Sunderland was called off due to high winds.
They will be doubly eager to return to action on Saturday, having seen their 100 percent home record in the league this season ended by Chelsea less than two weeks ago.
Chelsea are unlikely to return to the Etihad Stadium with quite the same swagger, however.
Jose Mourinho's side let slip an opportunity to extend their lead in the Premier League after drawing 1-1 at West Bromwich Albion on Tuesday and could be missing both John Terry and Gary Cahill due to injury.
"We are not happy because we drew 1-1, but that's football, that's life," midfielder Nemanja Matic told the Chelsea website. "Now we have to concentrate on the next training session and the next game."
There are two other all-Premier League ties in the last 16, with Sunderland hosting Southampton and Everton manager Roberto Martinez coming up against his former club, Swansea City.
Holders Wigan Athletic visit Cardiff City, while the lowest-ranked side left in the competition, third-tier Sheffield United, welcome Championship team Nottingham Forest to Bramall Lane.
Fixtures (1500 GMT unless otherwise stated)
Cardiff City v Wigan Athletic, Manchester City v Chelsea (1715 GMT), Sheffield Wednesday v Charlton Athletic, Sunderland v Southampton (1245 GMT)
Arsenal v Liverpool (1600 GMT), Everton v Swansea City (1330 GMT), Sheffield United v Nottingham Forest
Brighton and Hove Albion v Hull City (1945 GMT)