Southampton have the ball in the back of the net but Sekou Mara's attempt is immediately ruled out for offside. The decision is greeted by a huge roar at the Grimsby end.

Image source, Getty Images

Manchester United

Manchester United manager Erik ten Hag speaking on ITV1: "You are only as good as your last game and we have won one cup but we have to keep going."

On rotating the squad: "We have a squad and we didnt win the cup with eleven players we won it with a dressing room. We have so many games - I think the most games in Europe - so we have to use the squad."

On the FA Cup: "The FA Cup is so important for me it is so good, if you can win that you you have to give everything.

"It is about do or die it gives that sensation and the sensation to fight so you know what you are playing for."

On resting Marcus Rashford: "We have to keep [Marcus] Rashford fresh he has given so much. You can see how much he is giving but we have to keep him going and we will use him today definitely.

"From the bench he has had a really good impact and I expect that as well."

On the importance of scoring first: "It is all about the first goal we have to be ready to take that moment, so you are not making too many chances. Just one or two and you have to strike."

Michael Emons
BBC Sport at Old Trafford

There will be a host of presentations before tonight's game.

The Carabao Cup will be shown to the Old Trafford crowd by Harry Maguire and Bruno Fernandes.

The clean sheet kept in the final was David De Gea's 181st, taking him past Peter Schmeichel's club record of 180, and De Gea will be handed a special award by legendary manager Sir Alex Ferguson just before kick-off tonight.

Midfielder Casemiro and United Women goalkeeper Mary Earps will also be presented to the crowd.

Casemiro, who scored United's opener in Sunday's final, was named in Fifpro's World 11. Meanwhile, Earps was chosen as Fifa's Best Women's Goalkeeper after helping England win Euro 2022.

Off we go at Turf Moor.

Image source, BBC Sport

Tottenham are in decent form but this looks like a really awkward game for them.

Sheffield United are an aggressive side who will give it everything they have got and Bramall Lane will be rocking.

The Blades only just about avoided being upset by non-league Wrexham in the last round, but I think they will be the ones supplying the shock result this time.

Sutton's prediction: 2-1 after extra-time

Bit of a delay with kick-off at Burnley but they are having a minute's applause in memory of John Motson now.

After Southampton's fast start, Grimsby have settled into this.

Strong appeals for a penalty as Michee Efete goes down in the penalty area.

VAR is in operation in this game but nothing is given.

Image source, Getty Images

Paul Heckingbottom has said he is intrigued to see how players react facing a top flight team in tonight's FA cup game.

"The intrigue for me is who responds. Who does that out of the players on the pitch.

"What's been good for us this season is the work we've been doing on the training ground we've then seen it out on the pitch.

"It then gives you real confidence when you want to make changes whether that's the starting 11 or from the bench and I see this as as an opportunity for players to go show that they can deliver."

BBC One

They're about to go live from Bramall Lane on BBC One. Click the icon at the top of the page to watch.

West Ham United

West Ham United manager David Moyes speaking to ITV1: "I think this is the fifth time of seven that we are away to Manchester United. I think I will have to talk to whoever is sorting out those balls.

"Jarrod Bowen has a bit of an injury, he is on the bench but I didn't want to overdo it with him, so it is a chance for another player in the squad.

"I think Manchester United now have a squad and when you get that momentum and belief it makes it really hard to play against them.

"We were really close to them in the league here and I hope we can go one better and beat them this time.

"We want to go and give them a game it is a cup tie you don't get another bite at it so we have to be positive in our play.

"We played well against Forest scored some good goals so if we can take that into tonight that would be good."

77% possession for the Premier League club with 10 minutes on the clock. But so far so good for the League Two visitors.

Michael Emons
BBC Sport at Old Trafford

Image source, BBC Sport

It's been a tough campaign for West Ham.

The Hammers came seventh last season, two points and one place behind Manchester United, but this year has seen the London side in a relegation scrap.

But they come into this match after their best win of the season - a 4-0 success against Nottingham Forest. However, they will be without Danny Ings, who scored twice in that game, as he is cup-tied having played for Aston Villa in their shock 2-1 home loss to League Two outfit Stevenage in the third round.

David Moyes' side will also be without first-choice goalkeeper Lukasz Fabianski, out with a fractured cheekbone and eye socket, although Alphonse Areola is their cup keeper and would've probably played anyway.

Three-time FA Cup winners West Ham have not reached the last eight since 2016 and have to face a Manchester United side unbeaten in 10 matches in all competitions.

Moyes earlier this week said he would be "dad dancing and everything," if West Ham were to win a trophy this season so will he be celebrating a shock victory against his former side tonight?

Burnley have lost just twice since August, the most recent of which came in December when they lost 2-0 to eventual champions Manchester United in the Carabao Cup.

The Clarets are bidding to reach the quarter-finals for the first time in 20 years.

"There's times where you don't win and there's things you have to do to change that around," said manager Vincent Kompany.

"The journey towards winning is not something I'm afraid of, it's something I like. I can stay quite calm when things don't go well.

"That's not happened much this season but I've had to face that earlier in my career. That journey is something I enjoy, it makes everything clear. You know who's with you and not with you.

"You know that other people sometimes crumble on that journey and it's not just about yourself."

Image source, Getty Images

Fleetwood travel to Turf Moor also in decent form.

Since beating Sheffield Wednesday in a replay at the start of the month, they have won four of five League One games.

They have climbed into the top half of the table but former Celtic captain Scott Brown accepts that his side are underdogs tonight.

"Believe me, I've been an underdog at Celtic as well. And the same at Aberdeen. You always get underdogs winning a game or two. That's what we're hoping we produce," he told BBC Radio Lancashire.

"We're on a bounce of form at this moment in time and we've put together a few clean sheets. It's going to be extremely hard."

Four thousand Grimsby fans have been on the road all day and they're determined to enjoy themselves. "You're going down, you're going down," they sing to the home supporters.

Tottenham Hotspur

Tottenham last lifted a major trophy in 2008 but they start March fighting on three fronts.

As well as the FA Cup, they are fourth in the Premier League while they are still in the Champions League.

"If we can progress in the FA Cup then we will see what happens in the next round," said assistant boss Cristian Stellini.

"We have to try to win the game. It's an important competition, we take all the competitions seriously and we want to bring the same energy we had in our stadium to an away game."

Chris Mitchell: Interesting team selections in the FA Cup tonight. Fully expect Manchester United and Tottenham to go out with such weak teams. Surprising selections given this is the most open FA Cup in a long time.

Adam Kitchiner: Looks like Antonio Conte disrespecting Sheffiled United. Too many 2nd XI players.

Huge chance for Southampton!

A poor touch at the back lets in Sekou Mara but former Southport keeper Max Crocombe makes a fine save.

Grimsby haven't got going yet.

Image source, BBC Sport

What a job Vincent Kompany is doing at Burnley. They are not mathematically promoted yet, but they are 19 points clear of third-placed Middlesbrough and they are clearly going up - it's just a matter of time until it is confirmed.

The Clarets are flying in every way and they play great football as well. Their home form is so impressive too - they are unbeaten at Turf Moor all season .

That's another reason this tie is such a difficult one for Fleetwood, who have never been in the fifth round before.

They have beaten QPR and Sheffield Wednesday to get this far, and are six games unbeaten in League One - all of which is testament to how well Scott Brown is doing in his first job as manager.

Getting past Burnley is something else, though.

Sutton's prediction: 2-1

A reminder that Southampton have made nine changes. Too many? The Premier League club have started on the front foot and win a corner inside two minutes. Romain Perraud's attempt doesn't clear the first man.