Arsenal extended their unbeaten run to 19 games in all competitions with a rousing 4-2 win over Tottenham in the north London derby.
It gave Gunners boss Unai Emery victory in his first clash against Spurs, who are managed by his friend Mauricio Pochettino.
Here, Press Association Sport focuses on the two managers and how they got on at the Emirates Stadium.
Friends reunited
Emery and Pochettino have been friends since 2012 when the Spaniard recommended Pochettino as his replacement when leaving Valencia. Pochettino eventually turned down the chance to take over at the Vicente Calderon, but a friendship was born – the Spurs manager even advised Emery to come to the Premier League. Pochettino said their relationship has not been affected by their new-found rivalry and the pair shared a warm embrace before the game.
Big decisions
Both managers made a big decision in their team line-ups, with Mesut Ozil not featuring in the Arsenal squad and Toby Alderweireld named on the bench for the visitors. Although Ozil was said to have a calf strain, his omission intensifies the focus on his relationship with Emery after the Gunners boss suggested he does not fit into their 3-4-2-1 system. Given the volume of Spurs' fixtures, Pochettino had said he was going to rest players, but his decision to leave out Alderweireld was an eyebrow-raiser. The Belgian defender had started every Premier League game since August 18 and, with a home game with against Southampton coming up in midweek, it was a brave call to make
Poch the peacemaker
After Stephan Lichtsteiner got involved in Dier's equalising goal celebration it sparked a mass brawl on the touchline, with both sets of players and benches rushing over to defend their team-mates. There were some ugly scenes as Dele Alli and Matteo Guendouzi tussled, which led to Pochettino sprinting down the touchline from his technical area to play the peacemaker.
Gaining the advantage
Much of Arsenal's north London domination of the last two decades has been credited to the 3-1 win in Arsene Wenger's first derby back in 1996 and Emery will have been wanting to make impose himself in a similar manner. This was the perfect way to do it as the Gunners were far too good for Tottenham and he will be hoping it sets the tone as it did for Wenger. In contrast, Pochettino is yet to win as Spurs boss at the Emirates, although he will have another chance when they return here for a Carabao Cup game in a fortnight.
Half-time inspiration
Arsenal were staring down the barrel at half-time as Spurs' quick turnaround saw them lead 2-1, having ended the first half strongly. Emery responded by bringing on Alexandre Lacazette and Aaron Ramsey and it was an inspired decision. Lacazette scored his side's equaliser and the Welshman Ramsey notched two assists. Their introduction changed the course of the game and allowed the Gunners to register a famous win.
ga('create', 'UA-72310761-1', 'auto', {'name': 'pacontentapi'});
ga('pacontentapi.set', 'referrer', location.origin);
ga('pacontentapi.set', 'dimension1', 'By Jonathan Veal, Press Association Sport');
ga('pacontentapi.set', 'dimension2', 'cf5cce9f-f7e5-471d-9192-dde92bc4f19a');
ga('pacontentapi.set', 'dimension3', 'paservice:sport,paservice:sport:club-news,paservice:sport:football,paservice:sport:uk');
ga('pacontentapi.set', 'dimension6', 'story');
ga('pacontentapi.set', 'dimension7', 'composite');
ga('pacontentapi.set', 'dimension8', null);
ga('pacontentapi.set', 'dimension9', 'sport:football');
ga('pacontentapi.send', 'pageview', { 'location': location.href, 'page': (location.pathname + location.search + location.hash), 'title': 'Old friends, new rivals: how Emery came out on top in his tussle with Pochettino'});