Goals in the opening 10 minutes of each half, firstly from Jarrod Bowen and then a header from Michail Antonio, give West Ham a routine route into round five.

It will get much tougher in the next round for the Hammers though. Manchester United away.

James Collins crosses from the right for Derby, but Haydon Roberts, under pressure, can't get a clear header at goal.

Three minutes of injury time, but it's been all so routine since that second West Ham goal.

Chris Sutton
Former Premier League striker on BBC Radio 5 Live

There has been a lot of endeavour, heart and desire from Derby.

They've competed to try and nullify superior opposition but the link up in the final third hasn't been good enough.

We've had to wait 86 minutes for Derby's first strike on target and it comes from substitute Lewis Dobbin, but Alphonse Areola is right behind it and grabs the ball into his stomach.

A change for West Ham with Manuel Lanzini on for Pablo Fornals.

David Moyes can be reflecting on a very professional job from his side so far.

It's Newcastle away, Chelsea home, Tottenham away in their next three matches so Moyes will be very pleased he has been able to give midfielder Declan Rice a rest.

Chris Sutton
Former Premier League striker on BBC Radio 5 Live

It hasn't been perfect in terms of performance but this is a Derby team that have won their last six games and are gathering moment so it could have been tough.

There is still time for it to change but you don't feel it's coming. Derby haven't caused West Ham's defence enough problems.

Ten minutes to go and Derby need two goals to save this tie. They've not had a single shot on target so far tonight.

Emerson goes off, with Aaron Cresswell replacing him while Jarrod Bowen can reflect on a good night of work with a goal and assist.

He jogs off and 18-year-old striker Divin Mubama gets a chance to show what he can do.

Chris Sutton
Former Premier League striker on BBC Radio 5 Live

West Ham are really dominating now.

Benrahma coming on has sharpened things up for them. I think they have looked better in the second half.

A shot from a tight angle from Ben Johnson, but Joe Wildsmith in the home goal is down quickly to parry it away.

Ross: Why would Moyes not give Mubama a run after talking him up during the week? A like for like replacement with Antonio.

One final change for Derby. Jake Rooney, the cousin of former Derby manager and England striker Wayne, replaces Conor Hourihane.

West Ham midfielder Tomas Soucek sees yellow, sliding in late and catching the ankle of substitute Liam Thompson.

So nearly game over for West Ham. Jarrod Bowen, with a goal and an assist, has a chance to make it 3-0. He's eight yards out, but Joe Wildsmith gets a hand to the attempted placed shot to keep his side with a little bit of hope.

Lewis Dobbin instantly gets the ball, but none of three Derby players could have got their head on it. Although all three would have been offside.

Paul Warne has to do something so calls for a quadruple change.

On Eiran Cashin, Liam Thompson, Tony Springett and Lewis Dobbin.

Off Max Bird, Tom Barkhuizen, Nathaniel Mendez-Laing and Curtis Davies.

For West Ham, Said Benrahma, who scored the winner for the Hammers against his former side Brentford in round three, is on and Michail Anthonio goes off.

Image source, Getty Images

Chris Sutton
Former Premier League striker on BBC Radio 5 Live

Bird has been flying for them this season and he's hobbling off. That will be a big concern for Paul Warne.

West Ham's Ben Johnson is playing a risky game with a shoulder barge on Curtis Davies just inside of the penalty area, but referee Thomas Bramall says no.

We don't have VAR in action today as it's currently only used in this competition at Premier League grounds.