The tackles are flying. After Casemiro gets one for a high challenge, Diogo Dalot is booked three minutes later for hauling down Wilfried Zaha.

Boos ring around Old Trafford.

The initial corner is half-cleared. Arsenal keep it in play and Gabriel tries to get in behind but the flicked pass over the top rolls out harmlessly for a goal kick.

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Jude Bellingham has scored another scorcher for Real Madrid.

The future England captain nets after an incredible 40-yard run.

Real lead Napoli 2-1 in Italy.

Leandro Trossard plays a nice one-two but Jonathan Gradit comes sliding in crucially in the box to concede a corner.

While United are lively going forward, they still look vulnerable at the back. They should be leading. That was yet another poor goal conceded.

Fabio Vieira replaces Bukayo Saka, who heads off injured.

Hmm.

Bukayo Saka has been limping for a few moments and he's just gone down, calling for treatment...

He was a "doubt" for tonight's match but Mikel Arteta started him anyway.

Casemiro is too quick for Lucas Torreira but ends up getting clattered by the Uruguay international. It results in the first yellow of the game.

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Declan Rice spins away from Nampalys Mendy and Arsenal mount a good attack down the right with Bukayo Saka.

He slips it in for Takehiro Tomiyasu but his pull back is cleared.

Gabriel Jesus is given one to chase over the top with Kevin Danso but the centre-back does a good job.

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United have responded well since conceding. Mason Mount has a chance deflected behind for a corner.

Back to Wilfried Zaha, who has now scored four goals in his last five games against United (all for Crystal Palace in the Premier League), including netting twice in a 3-1 win at Old Trafford on 19 September 2020.

Adrien Thomasson was playing in the French third tier a decade ago. Now he's scoring against Arsenal in the Champions League.

He's been a threat for Lens and David Raya, though not faced with loads of shots, has been kept relatively busy.

More bad news for United fans.

It's now chucking it down. That means a lot of people are going to get soaked as the rain falls through Old Trafford's leaky roofs.

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Wilfried Zaha gestured towards United fans after scoring. They were booing but the former Crystal Palace man sparked scenes of absolute joy in the away end.

Izzy Christiansen
Former Everton and England midfielder on BBC Radio 5 Live

It has been all Manchester United, but this is poor defending. The ball is bouncing, it is pure strength from Wilfried Zaha and he holds Diogo Dalot off.

Andre Onana is nowhere to be seen, it bounces over his head and has gone into the back of the net against the run of play.

Simon Stone
BBC Sport at Old Trafford

I mentioned before the game that I thought Wilfried Zaha would care if he scored against his old club tonight.

I was right.

The former Crystal Palace man was far too strong for Diogo Dalot as the pair tussled on the edge of the area.

Zaha simply wanted it more.

Image source, Getty Images

Another Arsenal break through the middle. Gabriel Jesus links up with Martin Odegaard but his slipped pass through to Bukayo Saka is intercepted.