Leon Osman
Former Everton midfielder on Final Score

There's a real air of confidence about West Ham now they've gone 2-0 up and made it three and four goals. They're bringing youngsters on off the bench and giving them a run out.

The key is consistency, they'e on a terrific run but how many games can they keep winning. There is opportunity for them to keep performing at a good level and finish high because of how open the Premier League has been this season.

West Ham United

West Ham striker Oladapo Afolayan, who scored on his debut: "I am delighted it is a dream come true. it has been a couple of years of hard work since I joined the cub.

"I thought Ryan (Fredericks) was going to square it but he had a shot and I just followed it in.

"I played 60 mins last night for the U23s. When I came off I got told I was in the squad for today. I just had to go home and prepare. All I can do is come in every day and work hard and pray I get opportunities and take them.

"I have played in the FA Cup before. To score in the fourth round here is a dream."

West Ham United

West Ham assistant Alan Irvine, speaking to BBC Sport: "Very professional and strong. It is another clean sheet and another win. We are delighted that players who were given the opportunity to start have taken that. That is what you hope for. There is no way we would play a team we didn't think were strong enough. Full marks to them in the way they approached the game. They have strengthened their claim for places.

"He (Yarmolenko) is another answer. It was good to see him play there (up front). He has done it for Ukraine in the past. We know his talent."

On the young players who played: "Terrific. Two of the boys played yesterday for the U23s. It was special for all of them but especially for Oladapo (Afolayan) to get is goal.

"We have a squad of players who if we keep fit are strong enough to make changes. The FA Cup is a fantastic competition and vitally important that we try to do as well as we can."

Image source, Getty Images

Holders Arsenal out, Manchester United or Liverpool will exit on Sunday.

Manchester City will be licking their lips at the prospect of going all the way in the FA Cup again, won't they?

Plymouth boss Ryan Lowe: "We ran them close. To come here and go toe-to-toe with them and showcase what we've got, we did that.

"We missed a great chance in the first half, he's been scoring them of late, but you can't fault them. There's no shame to losing this 2-1 at Bramall Lane.

"Our main priority is the league. If there was another five minutes, who knows, but we've done everyone proud.

"I look up to Chris Wilder and Alan Knill, if I can achieve anything close to what they have I'll be alright and so will Plymouth Argyle."

Swansea City

Swansea City captain Matt Grimes: "It was a very professional performance. They had some very good players playing today but we wanted to keep the momemtum going from the league. 5-1 is as good as it gets."

On his first goal: "To be fair, I don't get many of them but I was confident on the edge of the box and thankfully it went in."

On potentially facing Man City next: "Yeah of course. As a player, you always want to play against the best players. There's not many better teams in the country better than Manchester City. It's a great step forward today."

Swansea City manager Steve Cooper: "That was the objective, to get through. We did it in style apart from not scoring the second half as well as we would have liked. We scored some great goals and a lot of young players were on the scoresheet too. We were more than good for the result."

On Liam Cullen's injury: "We will see how it is. Hopefully he's not too bad. I thought he was excellent today. To have those opportunities and take them as he did, we are not surprised but really pleased for him."

'Cheltnum' or as Pep says 'CHel-ten-hum'?

Sheffield United play Manchester United and Manchester City this week...

Sheffield United

Sheffield United manager Chris Wilder: "They had to chuck everything at us and we are disappointed with the manner of their goal. We had to have an attitude about us and we had that, it wasn't as comfortable as it should have been but we saw it out.

"It's the end bit again that has cost us. I've been involved in this cup many times as a player and a manager and these are not straightforward ties. They would have sniffed a result here today but the attitude and play was good. We just didn't go from 2-0 to 3-0 which would have seen it out.

"Indecision in a poor area, we've got to cut that out. It doesn't matter what level you play at you'll get punished.

"We are the architects of our own problems. Have you seen our fixture list?"

Jermaine Beckford
Ex-Leeds Utd striker on Final Score

Ten changes for Manchester City and I'm looking at the team sheet and it could be someone's first team. Cheltenham will be so excited to be playing against those players and I'm sure they will leave everything out on the pitch and make themselves and their families proud regardless.

This will be the first ever competitive meeting between Cheltenham and Manchester City. The Robins have lost all eight of their League Cup/FA Cup meetings with Premier League opponents.

Cheltenham are looking to reach the FA Cup fifth round for just the second time in their history, previously doing so in the 2001-02 campaign.

Man City have reached the fifth round of the FA Cup in each of the last five campaigns, last losing at this stage of the competition against Middlesbrough in 2015.

Michael Brown
Former Sheffield United midfielder on BBC Radio 5 Live

Overall United had a controlling performance, I would have liked a few more opportunities and there was a rally from Plymouth with some fight late in the game. But United controlled the game and deserve to go through.

Sheffield United

Sheffield United captain Billy Sharp: "We got sloppy at the end but fair play to Plymouth, they made it hard for us.

"Every game we aim to win so that's good but ideally we wanted a clean sheet. It's about trying to build confidence and put a run together. That's three wins in four games.

"We got tired, we should have gone on to get the third goal but they got it and pushed us. "

League Two Cheltenham sit 72 places below six-time FA Cup winners City.

Robins boss Michael Duff expects their opponents to have a bit of a culture shock when they arrive at Cheltenham.

"They'll be getting changed in a bar," he said.

"We'll make it as hospitable as we can and the one thing they will like is the pitch. You are not going to get a Ronnie Radford scene where it's a ploughed field.

"They will be able to play on it - we won't be training on it to make it as bad as possible. We do pride ourselves on playing good football, we are not going to ruin the pitch for this one-off."

Image source, Getty Images

Phil McNulty
BBC Sport chief football writer

The last shafts of sunlight are shining on Cheltenham's famous Cleeve Hill, normally synonymous with the famous horse racing festival, but today it is Cheltenham Town's football team taking centre stage as they face the might of Manchester City in the FA Cup fourth round.

Cheltenham manager Michael Duff has been dealing with split loyalties in his household as his 12-year-old son Tommy is a Manchester City fan.

A thrashing from Swansea City. They are into the next round where they could potentially face the mighty Cheltenham Town... or Manchester City.

West Ham cruise into round five and a tie against either Manchester United or Liverpool at London Stadium. They didn't look back from the moment Fornals gave them a second-minute lead.

All over! It could have been more comfortable but Brighton do enough to get the job done and progress into the FA Cup fifth round.

That's also two wins from two for the Seagulls, which could boost their confidence in their battle to retain their Premier League status.

And it will be the Blades, who see off a late surge from the League One side to make it through.