How Emery has revitalised Arsenal in all parts of the pitch

It was far and away the most exciting and encouraging result of Unai Emery's tenure at Arsenal so far.

Amid the kind of febrile atmosphere expected in a north London derby, Tottenham were blown away by an Arsenal performance of manic intensity, breathless speed and tactical dexterity.

The result saw the Gunners leapfrog their neighbours into the Premier League top four, while extending their impressive unbeaten sequence in all competitions to 19 matches.

There's no question Emery's Arsenal are more resolute and harder-to-beat than the often brittle teams put out by Arsene Wenger.

In just a few months, Emery has figured out how to extract maximum effort and reward from his players and appears to have a knack of making match-defining changes to tactics and personnel at just the right moment.

At the Emirates Stadium on Sunday, he introduced Alexandre Lacazette and Aaron Ramsey at half-time, transforming a match they were losing.

During the course of the match, Arsenal deployed three different systems, switching between them effortlessly depending on the flow of the match. It certainly left Tottenham outwitted by the end.

But there is a freshness and a ferociousness about Arsenal's play this season that suggests the Emery era will be a successful one.

Though it is surely too soon for Arsenal to be challenging Manchester City for the Premier League title this season, they can certainly make gains in one of the cup competitions.

We take a closer look at how Emery has revitalised Arsenal in all areas of the pitch.

GOALKEEPER AND DEFENCE

The facts and figures of the season so far suggest that Emery does have further work to be done in order to improve Arsenal defensively.

At this point last season under Wenger, they had kept seven clean sheets in 14 Premier League fixtures and conceded 16 goals. This season, it's just two clean sheets and 18 conceded.

But thanks to their greater firepower further up the field, the concession of these goals just isn't translating into defeats this season.

They paid around £17million to sign centre-half Sokratis Papastathopoulous from Borussia Dortmund over the summer, while veteran right-back Stephan Lichtsteiner arrived from Juventus on a free.

In addition, Bernd Leno was bought in for £19.2m to offer competition for Petr Cech between the posts and the German has successfully usurped Cech to become Arsenal's No 1 in the opening months of the campaign.

There's no doubt that Arsenal's back line does remain susceptible to opponents who counter-attack with speed and this is something Emery has acknowledged.

Though he remains stout in his belief that attack is the best form of defence - and that approach is paying off in their results - the likes of City and Liverpool have advanced to another level with their defensive stability this season.

Arsenal have some way to go in this regard but Emery hasn't had the same amount of time to develop his team in the way Pep Guardiola and Jurgen Klopp have. It will almost certainly be the next area he overhauls.

Things haven't been helped by Laurent Koscielny rupturing his Achilles tendon back in May and Shkodran Mustafi struggling for form at times.

At the moment, defensive liabilities aren't holding Arsenal back but reinforcements will be needed next summer.

MIDFIELD

Sunday's high-octane win over Spurs was a great illustration of how Emery has rapidly managed to overhaul Arsenal's midfield.

Wenger's Arsenal teams of recent years were frequently accused of lacking bite in midfield - essentially since Patrick Vieira moved on - and they were all-too-frequently overrun by good opponents.

That issue has been solved in part thanks to Emery's summer acquisitions and partly in his ability to get performances of tenacity and passion out of his players.

Lucas Torreira's shirtless celebration will become an iconic north London derby moment and his goal - Arsenal's fourth - capped a superb display by the Uruguayan in his first experience of the fixture.

The £25m Arsenal paid for Torreira in the summer is already looking like an excellent piece of business and - dare we say it? - his drive and determination could be in the Vieira class.

Both in his defensive disruptor role and in pushing Arsenal forward, Torreira was outstanding and it was no coincidence that Dele Alli and others had a quiet afternoon.

If terrier Torreira offers the bite, then Matteo Guendouzi supplies the abundant energy needed in any midfield.

Though the 19-year-old Italian only appeared off the bench on Sunday, he has enjoyed a highly impressive start to Premier League life.

Signed for just £7m from Lorient back in July, Guendouzi summed up the slick and efficient transfer business Emery conducted after being installed.

Instead of spending obscene sums of money on star quality, he chose to acquire players he believed were bespoke for the kind of football he wanted to play. We are starting to see the dividends of this.

One existing player of note in Emery's squad was Aaron Ramsey and his introduction from the bench at half-time on Sunday helped provide Arsenal with the thrust they urgently needed.

Plenty of fans raved about his performance post-match and it gets more and more baffling that Arsenal don't want to offer him a new contract.

The way Emery has boosted Arsenal's midfield, restoring both bite and creativity, means they are no longer reliant on Mesut Ozil to conjure some magic as Wenger's Arsenal often were.

The German, who apparently has a back injury, missed the Tottenham match and yet wasn't missed in the slightest. Arsenal seem to be much better off without his sulky presence.

FORWARDS

Emery resisted the temptation to splash the cash and strengthen his forward line over the summer, believing that he already had sufficient firepower in the form of Pierre-Emerick Aubameyang.

How right this assessment has proved, with Aubameyang's two goals against Tottenham increasing his season's tally to 12 in 18 matches.

The way Aubameyang finished off the second of his goals, drawing Arsenal all-square at 2-2, underlined his status as one of the world's deadliest strikers right now.

In fairness, he scored 10 in 14 last season after joining from Borussia Dortmund in January but he seems to have stepped it up another level under Emery.

Since he made his Premier League debut, Aubameyang has scored 20 goals in the competition. Only Mohamed Salah of Liverpool has scored as often in that time.

His minutes-per-goal ratio of 103.6 is superior to everyone else as well - including the likes of Salah, Harry Kane and Sergio Aguero.

He has been instrumental in an Arsenal attack whose sharp edge this season has seen them rack up 32 goals in 14 league games, more than everyone apart from City.

While Wenger's Arsenal would often demonstrate plenty of silky build-up without necessarily getting a goal, Emery's forward line don't mess around.

Alexandre Lacazette scored his seventh of the campaign against Spurs, while Danny Welbeck had scored five times before his latest injury.

With their front line in such good nick, Arsenal feel their can outscore any opposition at the moment and that confidence is reflected in their fine performances.