This would have capped things off.

Facundo Pellistri is played in but he's denied at the near post by Claudio Bravo, who has made some good saves tonight for Betis.

Simon Stone
BBC Sport at Old Trafford

There has been a bit of an issue in the away section, where police have gone in to try and quell a disturbance.

There were objects being thrown from both sets of fans and a few made an escape and a few were taken away.

It has not completely calmed down yet.

Lisandro Martinez gets to the near post to flick on Bruno Fernandes' delivery but it's over the bar. Decent effort.

Bruno Fernandes slips it through to Jadon Sancho. United win a corner as the fourth official shows another four minutes added on.

Ooh, not too far away. Casemiro tries to place it into the corner from outside the box but it trickles wide.

Simon Stone
BBC Sport at Old Trafford

There have been questions raised over why Facundo Pellistri has struggled to make an impact this season.

This is only his fifth appearance, all as a substitute, even though he played in all three Uruguay games at the World Cup.

That was superb from the 21-year-old, who could have played an easy pass back to the halfway line rather than embark on an arcing run that brought Manchester United their fourth goal.

Facundo Pellistri slips as he tries to slide in for a cross in the box and he catches Luiz Felipe. Looks a painful one but he's OK to carry on.

Leon Osman
Former Everton midfielder on BBC Radio 5 Live

You don't see a fourth goal celebrated like that very often but you can just see what it means for Wout Weghorst.

Facundo Pellistri does well to get to the byline, Scott McTominay forces a save with his first touch and it falls perfectly for Wout Weghorst to tap in.

Image source, Reuters

United have completely turned it around in the second half. The scoreline doesn't flatter them. They have created so many chances. Real Betis need to shut up shop and not concede any more.

Resting legs perhaps.

Scott McTominay is on for United, replacing Fred in midfield, while goalscorer Antony comes off for Facundo Pellistri.

Betis are clinging on a little bit. They still have a second leg at home and they don't want this lead extending.

William Jose is on for Juanmi as they switch things up again.

United have had so many chances.

Wout Weghorst takes it off William Carvalho in the middle. He lays it off to Antony on the right but he's closed down in time by Claudio Bravo.

Andrew Morris: Erik ten Hag should take off Casemiro before he gets suspended for the next game. No point running the risk at this point - plus give one of Manchester United's key players a rest.

Leon Osman
Former Everton midfielder on BBC Radio 5 Live

Wout Weghorst probably thought he had put another goal on the tally for Manchester United, if he went for the near post he probably would have.

He decided to go across the goalkeeper and gave the defender just enough of a chance to get a block on it.

He still can't score!

Wout Weghorst has a clear shot on goal when Luiz Felipe's block falls for him.

Felipe reacts, getting up desperately to stick a leg out and Weghorst takes too long, trying to place it into the corner, allowing the defender to get a crucial touch on it.

Aitor Ruibal is held off by Tyrell Malacia on the right as Betis have their first attack in a while.

United are looking to add another and they are dangerous.

Aaron Wan-Bissaka's cross is half-cleared but Antony's shot then lacks power as he tries to find the far corner.

Casemiro blasts one way over. He smiles as he jogs back for the goal kick.