London - Manchester City remained on course for the quadruple as they saw off second-tier Cardiff to reach the last 16 of the FA Cup on Sunday while Manchester United and Chelsea also advanced over the weekend.
Liverpool were dumped out of the world's oldest senior knockout football tournament and it needed a Harry Kane equaliser eight minutes from time to ensure Tottenham remained in the hat after they were held to a 1-1 draw by lowly Newport.
Below are five things learned from the fourth round of the FA Cup:
'VAR' THE STAR
A system designed to aid referees ended up taking centre stage at Anfield as West Bromwich Albion beat Liverpool 3-2. Once referee Craig Pawson started to use the technology it seemed he could not stop with several incidents leading to long and frustrating delays for fans and players alike as the new system is receiving a trial in English cup competitions this season. Pawson used VAR to deny West Brom's Craig Dawson a goal for offside by Gareth Barry. Pawson then become the first English referee to consult a touchline monitor himself before awarding Liverpool a penalty for a foul on Mohamed Salah by Jake Livermore. There was yet another VAR review prior to the break, before a Joel Matip own goal that put West Brom 3-1 up was allowed.
UP FOR THE CUP
There have long been concerns that the FA Cup is being devalued by leading teams fielding weakened sides in earlier rounds as they look to cement their positions in the Premier League or turn their attention to even bigger European prizes. But one with Manchester City seemingly running away with the Premier League title this season, their rivals know the FA Cup could represent a better chance of silverware. Chelsea and United responded by fielding strong sides in their fourth-round Cup ties.
SANCHEZ SIZZLES BUT WHO MISSES OUT?
Alexis Sanchez had a debut to remember for Manchester United in a 4-0 win against lower-league Yeovil Town, adding panache and zip to the Red Devils' attack. Jose Mourinho can't possibly fit all his attackers into the team, meaning the likes of Marcus Rashford and the in-form pair of Anthony Martial and Jesse Lingard could lose game time. But that's clearly not a problem for the United boss, who appears lifted by the signing and sees the Chile international as a key cog. "Good players want good players," said Mourinho after the Yeovil win. "We have a fantastic group of attacking players and he is another one with more maturity and experience."
DE BRUYNE'S BRAIN
There has been plenty written already this season about Belgian star Kevin De Bruyne's brilliance but amid all the dazzling skill displayed by the Manchester City playmaker there is also a player of considerable nerve, as well as intelligence. It is one thing to attempt to slide a free-kick under, rather than over, a defensive wall when your side are already several goals to the good or there's not much riding on the game. But to do so just eight minutes into a Cup tie away from home when it's 0-0 and your side are pushing or a "quadruple" takes a certain amount of "bottle". Yet there was no fear of failure when De Bruyne put City ahead with a brilliantly conceived and executed free-kick. "The wall was not nine metres away from me and so they were very close and it was easy to put it under," said the modest goal-scorer.
It is very easy to be cynical about phrases such as the "Magic of the FA Cup". Yet no one who saw the excitement on show at Rodney Parade as Newport held Tottenham to a 1-1 draw - to earn a money-spinning replay at Wembley - could doubt the elation of their loyal and often long-suffering fans.