Sead Kolasinac, who was also on a yellow, is smartly replaced by Ainsley Maitland-Niles.

Dominik Kohr breaks down another Arsenal counter-attack, brings down Bukayo Saka and he's shown a second yellow. He's off!

Image source, Reuters

Arsenal almost get a second. Bukayo Saka's half-volley from a few yards out hits the keeper's feet.

From the resulting corner, Pierre-Emerick Aubameyang is inches away from poking in a cut-back from the left.

Filip Kostic is certainly not short of confidence. He travels down the left with the ball and tries to pick out a teammate in the centre.

He can't find them but the clearance falls for him on the edge of the box and he attempts an overhead kick. It's always sailing wide.

The cards are coming out again. Sead Kolasinac holds on to a throw-in too long and goes into the book for time-wasting.

Seemed a bit harsh.

Frankfurt's fans are still at it. Chant after chant. I'm getitng a headache!

On the pitch their team has another corner but it comes to nothing as Danny da Costa half-volleys it way over the bar.

Image source, Getty Images

Arsenal's Dani Ceballos replaces Joe Willock. A fine outing from the young midfielder. He looks disappointed to come off too.

Image source, Getty Images

Calum Chambers tries to provide it. The full-back makes a run down the right and swings a lovely ball into the box.

It sits perfectly for Pierre-Emerick Aubameyang to volley but the striker fluffs his effort. He's furious with himself too. A tricky one that though.

Arsenal are penned in their own half. They need to do something to end the pressure - no outlet at the moment.

Simon Stone
BBC Sport at Old Trafford

FC Astana are the first side from Kazakhstan to play Manchester United.

They will be cheered on by 230 supporters - who might not have actually flown in from Kazakhstan. However, those who have are halfway through a 6,000 mile round trip. In other words, it would take less time for Astana to travel to Shanghai.

Filip Kostic receives the ball in space on the left and there's absolutely nobody near him. He has so much time so hits it.

It skims inches wide of the keeper's left post. Arsenal let off the hook again.

Moments later, substitute Goncalo Paciencia drills it straight at Emiliano Martinez.

Goncalo Paciencia replaces Bas Dost for Frankfurt. He'll still be raging about that miss earlier...

Joe Willock is the next player to go in the book for a sloppy tackle on the left. Frankfurt will fire one in from the free-kick and Arsenal have some defending to do.

Sho: Andre Silva is gonna need at least another 10 chances to score. His finishing is atrocious.

Tim Sherwood: I met a Frankfurt fan a few years ago in the airport hotel's cigar bar (which I highly recommend). He told me that it wouldn't be long before a German cup final, and then a European cup final. Well Rufus, I hope this year is that European final

Image source, Reuters

Simon Stone
BBC Sport at Old Trafford

That Manchester United starting line-up is a bit sobering.

No fewer than six players were born after the 1997-98 season started. In other words after Eric Cantona played his last game for the club.

That is both amazing and awful.

And now Nicolas Pepe wins a free-kick in the opposition half as Dominik Kohr goes in late and gets a yellow card for it.

Image source, Reuters

Nicolas Pepe almost makes an immediate impact. He sprints to the right touchline to keep an overhit cross in, then is played through in the box.

He tries to cut inside but Makoto Hasebe sticks a toe out.

Arsenal's record summer signing Nicolas Pepe is on. He replaces youngster Emile Smith Rowe.

What a chance!

Frankfurt attack down the left and a cut-back comes all the way through to Andre Silva at the back post.

He blasts it over the bar first time.

Granit Xhaka whips a free-kick in from the right and there's plenty of height on it. It flies all the way over the players and bounces off the crossbar, taking the keeper by surprise as he'd lost flight of the ball!