Napoli dazzled by Emery's Europa League magic as Valencia reunion set up
Napoli 0 Arsenal 1
You tend to get what you pay for in football and in hiring Unai Emery, Arsenal have paid for the man who knows more about the Europa League than any other.
The competition is practically under Emery's ownership, given his three consecutive titles with Sevilla, and a change of clubs and countries has done nothing to loosen his grip.
Against a manager as experienced as Carlo Ancelotti, and a team as talented as Napoli, Emery's Arsenal have delivered a two-legged lesson in attacking precision, defensive balance and emotional control.
They came expecting an Italian storm in Naples but it was the visitors who provided much of the attacking thrust.
Napoli were never able to pour forward, never allowed to attack with the conviction that might have troubled the Arsenal back-line.
The storm became little more than a breeze for the visitors, who did the hard work at home last week and then played with a composure that has generally been missing on the road this season.
It all made for one of Arsenal's most complete, professional away performances of the season.
Alexandre Lacazette's superb first-half free-kick put the tie beyond Napoli, who needed four goals in the second half but, frankly, might have needed four hours to score one.
Valencia are next, the last opponents blocking Arsenal's path to the Europa League final. They will be familiar foes for Emery, who managed there from 2008 to 2012, and Arsenal will carry no fear after this deconstruction of Napoli, the second-finest team in Serie A.
It was through bold, front-foot football that Arsenal reached this stage of the competition, coming from behind to defeat both Bate Borisov and Rennes in previous rounds.
Bravery has been the name of the game in these knockout rounds and it was no different here, even if Arsenal had a lead to defend this time rather than a deficit to overturn.
Emery had made his intentions clear in the build-up to this meeting, declaring his desire for an away goal that would make Napoli's task so much more difficult.
The Spaniard was not kidding. Out came the big guns for Arsenal, with Lacazette and Pierre-Emerick Aubameyang starting in attack away from home for the first time since February 3.
No manager has won as many games in the knockout stages of this competition as Emery, who clearly wanted to make it 26 victories here, despite the first-leg advantage.
Emery's side had come to play, then, but they also knew they had to battle.
An enormous banner urging Napoli to "fight and win" had been held up in the home end before kick-off, and there was a genuine sense of nervous tension in the early exchanges.
Emery could be seen hopping on the spot, gurning in frustration, when Aaron Ramsey misplaced a forward pass.
In truth, he need not have stressed. For 20 oddly serene minutes, Arsenal were composed and calculated, pinning Napoli back and cutting off their passing options.
There was a threat from the home side but it was nothing like the onslaught that the travelling Arsenal fans, around 1,000 of them, would have been fearing.
The main moment of danger came from an Aubameyang error, losing the ball on the edge of the Napoli box and triggering a counter-attack that ended with Petr Cech saving from Jose Callejon.
Arkadiusz Milik then headed wide when he should have at least hit the target, but few would have claimed that Arsenal were not deserving of the lead when it arrived.
The loss of Ramsey to injury did little to harm their flow, and Lacazette promptly swept his 25-yard free-kick, which he had won by himself, into the top corner.
He was helped by Napoli's Alex Meret, who committed that old goalkeeping sin of taking a step one way and then watching, off-balance, as the ball went the other.
So Napoli needed four. Before the game, that might not have felt like a complete impossibility. At half-time it felt well beyond the capabilities of Ancelotti's side.
Their night should have worsened considerably a few minutes after the break when Henrikh Mkhitaryan's cross found Aubameyang, totally free, with the whole goal to aim at.
Meret's subsequent save, flying across his goal, was Napoli's best individual moment of the night.
Napoli knew the game had gone long before the end. They created a couple of half-chances as it faded to a conclusion, with Milik again missing the pick of the bunch, but Arsenal were never forced to scramble.
Their control of the tie never looked like disappearing, and Emery was even able to remove Lacazette and Granit Xhaka in the second half.
Such was their mastery of the occasion that they could even start thinking ahead to Sunday's meeting with Crystal Palace. (© Daily Telegraph, London)