Arsenal beat AC Milan 2-0 at a raucous San Siro in the last 16 of the Europa League in one of the most unexpected results in their European history.

First half goals from Henrik Mkhitaryan and Aaron Ramsey stunned Gennaro Gattuso’s side to put the Gunners in a commanding position for next week’s second leg.

It was a performance full of character and courage in front of 72,821 fans but also featured no little skill and tactical discipline as the Arsenal backline held their shape while the midfield hassled and harried the home team to an extent which had the frustrated home fans howling their displeasure long before the final whistle.

But Arsene Wenger’s men held on to surprise everyone – not least themselves after a dismal four defeats in a row.

Things looked even worse when it was discovered Hector Bellerin was missing from the line-up after inflaming the ligament in his left knee.

Cup goalkeeper David Opsina returned in place of Petr Cech, who took it upon himself to apologise on social media for his poor performance in the 2-1 defeat at Brighton on Sunday.

While it showed that his powers may be slowing as he ages, his character is as strong as ever. However, if paying penance on Twitter is the way forward then many of his colleagues should be glad the number of characters has increased from 140 to 280 such is the space required these days to list their failings.

Record signing Pierre-Emerick Aubameyang, who, despite playing for Borussia Dortmund in the Champions League was ineligible – as UEFA rules state a club dropping into the same competition as a player’s new team is classed as cup tied – giving Danny Welbeck a starting berth.

Aaron Ramsey came in for the increasingly disappointing Alex Iwobi as Wenger fielded a strong side to keep his side’s season alive – for another week at least.

With Arsenal 30 points off champions-elect Manchester City and perhaps more damningly 13 off fourth placed Spurs the Europa League had been seen by many – if not Wenger – as the club’s best chance of silverware this season.

We were to find out if that dream was to stay alive after 90 tumultuous minutes in the San Siro – which will go down in Gunners folklore.

But first players and supporters honoured the memory of the late Fiorentina captain Davide Astori who sadly passed away in his hotel room at the weekend.

As both sets of fans applauded, as is the custom, the Milan Ultras massed on the gigantic Curva Sud held up a banner which read: ‘United in the pain of the Astori family. Rest in peace.’

There was no such charity or respect shown to Arsenal by Milan once the game started as the 24-year-old German-born Turkish international Hakan Calhanoglu ran at the backpeddling Gunners defence.

With the noise levels set to ear-splitting Patrick Cutone powered down the right side of defence into the box before firing the wrong side of Ospina’s post.

Cutrone has had a breakthrough season to remember at the San Siro as the 20-year-old has impressed with 14 goals in all competitions this season.

However it was Arsenal and Mkhitaryan who impressed shortly afterwards as he fired the ball into the net past the highly-rated Donnarumma to put the Gunners 1-0 up on 15 minutes – sending the travelling fans into raptures and considerably lowering the noise levels from the home support.

The former Manchester United man showed flair to cut inside and shoot after receiving the ball from an astute Ozil pass to make it seven goals in his last 12 Europa League matches.

On the half hour mark Milan probed but Giacomo Bonaventura fired wide.

The 22-year-old has formed an effective midfield partnership with Franck Kessie, scoring 10 goals between them this season and picking up a combined seven assists.

It was interesting to watch the pair dovetail well, combining to put Arsenal on the back foot at times.

Yet Arsenal should have been 2-0 up before half-time after good work had been shown in powering down the left flank by Welbeck as he raced towards Donnarrumma’s goal.

Yes the angle was tight, but top centre-forwards thrive on those type of chances which Welbeck failed to convert by firing directly at Donnarumma.

Incredibly the snatched shot wasn’t to be rued as Ramsey drove into the box and jinxed and turned before pushing the ball past a despairing keeper to slot home in front of an empty net to make it 2-0 moments later – sending the Arsenal fans here at the San Siro into dreamland.

Referee Clement Turpin blew shortly afterwards for half-time but the scoreline was anything but daylight robbery.

There were a number of disappointing performances from the home team, from players who had excelled his season – none more so that Suso.

For someone having such an impressive season with eight goals and 11 assists from a wide position the former Liverpool player was hugely disappointing.

There was little evidence of his trademark trickery from the flank from the Spaniard who has flourished since returning from Genoa on loan two seasons ago.

Early in the second half Davide Calabria pushed forward and played the ball through to Bonaventura who fired over.

It was a reminder to Arsenal they had to keep their shape.

However, Arsenal kept battling and denying time and space to their rivals as the home side started to make unforced errors which in turn frustrated the vociferous home support.

As Turpin blew for full-time Milan looked confused and dejected, the victims of a classic smash and grab by a determined Arsenal side – and my how everyone associated with the club enjoyed it.