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Chelsea beat Chesterfield in round three, while Plymouth knocked out Birmingham
Tuchel tests positive for Covid and misses tie
Plymouth are seventh in League One
Chelsea are eight-team winners, last in 2017-18
Plymouth's best FA Cup run saw them reach the semi-finals in 1983-84
What a day.
Twelve ties, 34 goals, and a bucket load of drama.
Kidderminster did themselves proud, Frank Lampard's Everton reign is off to a winning start, and Chelsea suffered a scare before the European champions overcame League One Plymouth.
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We're back tomorrow with three more FA Cup ties.
Until then...
FT: Tottenham 3-1 Brighton
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There are a further three FA Cup ties to come on Sunday:
12:00 GMT: Liverpool v Cardiff City
16:00 GMT: Nottingham Forest v Leicester City
18:30 GMT: AFC Bournemouth v Boreham Wood
FT: Tottenham 3-1 Brighton
Tottenham Hotspur
Tottenham boss Antonio Conte, speaking to ITV4: "To win in an important competition like the FA Cup is so important, it is important for the confidence, important to get a win against a really good team.
"It was good, Kane scored twice. We had chances to improve the final result but in the end I think it was fair.
"In games when he [Harry Kane] didn't score he always plays for the team. He played a fantastic game for us, he is an important player for us because he is fantastic quality and to score is important because he is a No 9. It was good for Harry.
"We have to continue and now we prepare for a tough game against Southampton on Wednesday."
FT: Tottenham 3-1 Brighton
Brighton & Hove Albion
Brighton boss Graham Potter, speaking to BBC Sport: "Our performance wasn't one of our better ones and I thought Tottenham were good.
"I have no complaints, we just weren't at our level. You can't give away three goals and expect to win the game.
"We wanted to go through but we have played a really good opponent with really good players."
A reminder of the teams through to the fifth round so far:
Middlesbrough
Chelsea
West Ham United
Crystal Palace
Everton
Huddersfield Town
Manchester City
Peterborough United
Southampton
Stoke City
Norwich City
Luton Town
Tottenham Hotspur
FT: Tottenham 3-1 Brighton
Tottenham are back in action on Wednesday. They host Southampton in the Premier League (19:45 GMT) while Brighton have a full week to prepare for next Saturday's league game at Watford (15:00).
FT: Tottenham 3-1 Brighton
Tottenham Hotspur
Two-goal Harry Kane, speaking to ITV4: "Obviously we're delighted with the result. We played really well. We started on the front-foot and missed a bit of momentum in the second half but controlled the game after our third goal."
"I was delighted to see that go in [first goal]. I'm happy to be on the scoresheet. It was unbelievable by Sonny [for the second goal]. He has lots of pace and created a big chance and I'm just happy I was able to sneak it home. Everyone played really well. Let's keep it going.
"There is still a long way to go [this season]. We have plenty of games coming up in the league and cup."
On Antonio Conte: "He he has been brilliant. I cannot speak highly enough of him and he has really changed the mindset of the team. We have to keep working hard on and off the pitch."
FT: Tottenham 3-1 Brighton
Don Hutchison
Ex-Liverpool midfielder on BBC Radio 5 Live
The scoreline could have been anything; 6-3, something like that. In the end, Spurs deserved their win; Harry Kane looked really sharp, Son was incredible. In the middle of the pitch, Hojbjerg and Winks were OK. As soon as Bentancur came on, he provided that little bit of quality. Yves Bissouma was Brighton's best player by a mile.
FT: Tottenham 3-1 Brighton
Well deserved win. Tottenham were the better team overall. Poor start by Brighton who came good at the start of the second half but conceded a third soon after scoring.
Tottenham 3-1 Brighton
Tottenham march into the fifth round. Brighton crash out.
Tottenham 3-1 Brighton
Glancing header by Danny Welbeck which forces Hugo Lloris to scramble across his line to keep out. Too little too late for Brighton.
Tottenham 3-1 Brighton
Corner to Brighton but it's over-cooked and ends in a throw-in to Spurs.
Tottenham 3-1 Brighton
Harry Kane is about 22 yards out. Is this the hat-trick? High and wide.
Tottenham 3-1 Brighton
Five additional minutes. Tottenham are almost there.
Rob, get a grip!
Deborah, Primrose Hill
Tottenham 3-1 Brighton
'Oh when the Spurs go marching in'.
Tottenham fans are in great voice in the closing stages.
Another chance but Sergio Reguilon is denied by Robert Sanchez.
Tottenham 3-1 Brighton
Rodrigo Bentancur picks up his first booking in English football. I suspect it won't be his last. He's snapping at the ankles of Yves Bissouma and the referee doesn't like it.
Matt Doherty has come on for Emerson Royal.
#bbcfootball or text 81111 (UK only - standard message rates apply)
Nicholas Walker: I’d like to withdraw my feeling “safe” statement and apologise to all Spurs fans for ever thinking this! Oops!
Nicholas' right of reply. The two-goal cushion is back.
Tottenham 3-1 Brighton
Steven Bergwijn threatens to bulldoze his way through the Seagulls defence.
Five minutes left plus stoppages for Harry Kane to get his hat-trick. Will he do it?