More from Oxford boss Karl Robinson to BBC: "I don’t think our goalkeeper was overly worked. Our two centre-backs were amazing. We had a very young back four, in fact the whole team is very young. It is testament to the board and to the patience of the fans that they have allowed these young players to grow together and to make mistakes.

"I feel they will one day go on to bigger and better things, but I hope not right away and we can build with these players for a while yet.

"But we’ve not achieved anything. It’s so easy to stand here and take the plaudits, but we feel we have not done anything yet. If we stop the season now, we will have amazing memories, but we want a great summer and to do that we have to be promoted.

"They will be aware of the quality we have, but we know how good they are. We have seen glimpes of the top level football they can play so won’t be taking anything for granted in the replay."

A decent win for Portsmouth!

Norwich City

Norwich boss Daniel Farke, speaking to BBC Sport: "We are delighted. It is a difficult place to come. It was a well-deserved win and it was a top performance.

"We played fantastic in the first half. Even in the first minutes of the second half we were on the front foot and scored two wonderful goals. It was a top class delivery for the first goal and a cool finish from Grant, especially against a side so good at set-pieces."

On Josip Drmic: "Our numbers are quite decent for goals. Some players are not always dancing on the tables because they are not playing but to give a class and committed performance as good."

On Cup run: "It is good for the confidence and the mood. It is the first time in several years we are in the fifth round of the Cup. We try to do everything to work on our little miracle and stay in the league. A cup run might help."

Newcastle United

Newcastle boss Steve Bruce speaking to BBC Match of the Day: "Frustrating, disappointing. We didn't do enough basically. Oxford you have to say well done to them they came and made it difficult for us but this is one of those where we didn't play well enough. We are still in the hat and we will go there and I am sure be better than we were tonight.

"We didn't pass the ball well enough, we didn't create enough. It was one of those afternoons where too many of them didn't get to a level they can.

"It is disappointment for all those thousands that came today and we didn't play well enough to get in the tie. It was a poor performance all round.

"Oxford have some good players, they are well organised and well drilled.

"It is what it is. We can't make many changes because of the injuries we have. We accept we have had a tough time with injuries so we will be as strong as we can be."

Oxford United manager Karl Robinson speaking to BBC Match of the Day: "Its incredible. We’ve played three Premier League teams this season and only one of them has beaten us – Manchester City. So I have got to give credit to my players.

"For the fans who turned out, it just shows you this cup has got a wonderful presence. My players were exceptional. Probably say we got the best chance of the game. All in all a very good performance by my players and I am very pleased with them.

"I thought we tried to play, which was brave of the players. We started nervously and I wasn’t happy. I told them to relax and once they did that they got to grips with the game a bit more."

Sheffield United

Sheffield United manager Chris Wilder: "It was always going to be a difficult game this. There's been some victims over the last few years coming here and getting turned over. I thought our attitude was excellent. We talked before about the team talk their changing room would be having about us being a soft Premier League team and us not enjoying the pitch and our players certainly didn't let it happen.

"I thought the atmosphere was brilliant, I love coming here. It's great, it's raw.

"I didn't think it was a great game. We were pragmatic in our approach. We needed to show plenty of things to get the result today.

On going forward in the competition: "If we could get a home draw, with it being a midweek game with all the travel associated, we'd take that. But to go far in this competition there are hurdles you have to overcome.

"Momentum is key. We want to win games of football. Our changes show you what our boys are like. There are some good players not getting game time at the moment. Every game is an opportunity to grasp and some players grasped that opportunity today."

BBC iPlayer

If you want to watch all the goals from this afternoon, they are doing a goals loop on the 'FA Cup Channel' from 17:30 GMT which is running on the BBC iPlayer all day.

Just follow this link to watch online.

Millwall manager Gary Rowett: "I'm a little bit disappointed overall. I didn't think there were massive amounts in the game. I think they were just a little bit more forceful. We knew their mentality would be brilliant but I thought the game was pretty even.

"The first goal was a really poor goal for us to concede. We made a mistake and backed off and it was an excellent finish. I was a little bit disappointed.

"The more we chased the game the more open we became. We just couldn't find that little bit of quality, we just huffed and puffed a bit and couldn't find that quality.

"We had one or two players come into the team today that maybe didn't do enough to keep their place in the team. But hats off to Sheffield United, two moments of quality have done for us."

BBC Radio 5 Live

Nine games down, one to go.

There's commentary from 17:30 GMT of Hull City v Chelsea on BBC Radio 5 Live.

Tottenham Hotspur

Tottenham manager Jose Mourinho speaking to BBC Match of the Day: "They are a good team., they play at home and they react. They put some pressure on us in the last minutes. The ball didn't go out for about five minutes. They scored. But we are alive.

"Our fantastic fans that came here today, plus the other 50,00 that will go to the match at home, will be happy we have one more match. We are going on that difficult way! We are working. We don't need one more match but we have it so we are going to fix it. This is the way it is. It's better to draw than to be out. We have a match at home which is difficult of course, but better than losing.

"We had to wait for chances to score. Good transitions, good passing, good positions then we had Son Heung-min who missed by a few inches and the keeper made a good save. They have a style of play which is very direct and very aggressive. We improved bit by bit in the last few matches, we didn't concede [in recent games]. We conceded in the minute of 80-something today but we are not scoring enough goals for the chances we create.

"They did exactly the same. They chose their best team and played at the maximum strength which is the way to respect the competition. We don't need one more match but we have to play. Both of us prefer to have the next match then not have it. The desire to do it [win the cup] is the same for everyone. I believe that in the next round it will be a massive number of Premier League teams."

Burnley

Burnley boss Sean Dyche, speaking to BBC Sport: "It is a strange one. Ding dong first half with two teams missing chances. But we really let it go second half. We responded well to their goals but didn't ask enough questions in the final third. We turned over the ball in a bad position. Those connections are not always as clear when you change the side a lot but we still put a good side out.

"They had a chance straight from kick-off, which was sloppy by us. But we had chances. There were a lot of maybes. We got into the final third in good positions, but overhit crosses. It has been a massive week in the league and felt we could win it but couldn't get it over the line."

Sheffield United

Image source, Getty Images

Sheffield United midfielder Oliver Norwood: "We knew it would be difficult. Since the new manager came in they'd been in a good run of form. We came with a game plan and we've got the job done and we're in the hat.

"We want a home draw, we'll take anyone, I'm not too fussed who we get. There is no reason why we can't go all the way this season. We need a few more points in the league, we're not just settling for safety but a cup run is good for the football club."

On Mo Besic's goal: "It was a fantastic finish. Mo has came in the last few games and done a great job. That's what the manager needs, players pushing for spots in the team. It's a wonderful finish with his weaker foot."

On his goal: "I think I hit on the volley there were that many bobbles out there! I was screaming at Sharpy to lay it off to me. As soon as I hit it I knew it was in."

Plenty of eyes on Hull winger/forward Jarrod Bowen tonight. He's long been linked with a move to the top flight.

Hull: Long, McKenzie, Burke, Tafazolli, Lichaj, Da Silva Lopes, Kane, Honeyman, Bowen, Wilks, Eaves. Subs: Grosicki, Ingram, McLoughlin, Kingsley, Magennis, Irvine, Samuelsen.

Chelsea: Caballero, Azpilicueta, Zouma, Tomori, Alonso, Barkley, Kovacic, Mount, Pedro, Batshuayi, Hudson-Odoi. Subs: Christensen, Willian, Cumming, Emerson Palmieri, Gilmour, Lamptey, Maatsen.

Referee: Craig Pawson (South Yorkshire)

ToTheManorBorn: Great result. Really organised display. So good to hear ‘Come on you yellows’ ringing around St James’ Park. Well done to all those that followed the “Mighty Us”. Where were the NUFC fans???

One more game to come!

The KC Stadium looking slick under the lights as we build up towards the late game.

A reminder that Chelsea have made eight changes as Michy Batshuayi leads the line.

Emlyn Begley
BBC Sport at St James' Park

Boos from the Newcastle fans at full-time. Cheers from the large Oxford contingent, who have stayed behind to sing and celebrate a good performance and result.

The Magpies need to win a replay at the Kassam Stadium if they are to reach round five for the first time since 2005-06.

Leicester are also in the hat for the fifth round draw.

They picked up a narrow win over Brentford earlier today. Here's the highlights.