Arsenal moved back to within two points of Premier League leaders Manchester City after producing a rousing second-half display to beat Watford 3-0 at Vicarage Road.
Alexis Sanchez opened the scoring on 62 minutes as the Gunners finally broke the hosts' resistance, before Olivier Giroud added a second shortly after coming on.
Aaron Ramsey completed the scoring on 74 minutes by bundling home a third as Arsene Wenger's side reclaimed second spot in the table from Manchester United.
Here, Sports Mole determines how the points were won in this London derby.
Match statistics
WATFORD
Shots: 8
On target: 1
Possession: 33%
Corners: 3
Fouls: 11
ARSENAL
Shots: 17
On target: 6
Possession: 67%
Corners: 9
Fouls: 12
Was the result fair?
The cream rose to the top. It is that simple. There was little to choose between the sides at the break, with Watford giving as good as they got, but the quality of Arsenal began to shine through. The result, nor the scoreline, flatters Arsene Wenger's side. It should, given that it was 0-0 by the hour mark, but it was men against boys for the final half-hour or so and, in truth, Watford never had a chance once their opponents stepped it up a gear.
Watford's performance
In short, Watford gave up the ghost as soon as Sanchez opened the scoring and Quique Sanchez Flores will be more disappointed with the capitulation than the result. Prior to that goal, the Hornets were every bit as dangerous as their visitors. They might have even earned a half-time lead had Odion Ighalo - who has netted five Premier League goals this season - done better with his one-on-one with Petr Cech in the first half. But as soon as Sanchez scored that was it. Such a setback deflated the hosts, who had looked defensively sound for some 62 minutes.
There were positives; namely in the no-nonsense approach from Troy Deeney up front, and Etienne Capoue in midfield, but the second-half collapse is worrying. If their collective head drops after falling behind in their remaining 29 top-flight outings then a swift return to the Championship is guaranteed.
Arsenal's performance
It may have taken a while, but once Arsenal clicked, it was ever so easy for Wenger and co tonight. It was so easy that the first half, in which they were troubled on a number of occasions, feels like it was part of a different match, such was their struggles inside the opening 45 minutes.
Theo Walcott led the line to little effect, while Ramsey missed a glorious chance to open the scoring. At the other end, Laurent Koscielny did not look like a player who had missed a couple of weeks through a hamstring injury, with the Frenchman excellent alongside the assured Per Mertesacker. But Watford still caused problems, and if not for Ighalo's wayward finish then Wenger and co might have been a goal down at the break.
It was a different story after the interval. Arsenal's creative outlets in the form of Santi Cazorla and Mesut Ozil began to express themselves, and the duo combined for the opener. Cazorla's lovely disguised ball saw the German run through on goal, before being fouled by Nathan Ake. Before referee Mike Jones could blow for a penalty, Sanchez stroked home at the back post. From there, it was easy.
Giroud replaced the ineffective Walcott and blasted home Ozil's excellent cutback within minutes of his arrival, before Ramsey then finished it off. It was the Gunners' 11th league goal in their last three games. It was the same scoreline from their win over Manchester United last time around, but a very different victory and Wenger can be pleased.
Sports Mole's man of the match
Alexis Sanchez: Few stood out, but none stood out more than Sanchez, whose opening goal sent Arsenal well on their way. The diminutive Chilean was not always productive tonight, but he was always lively and comfortably the stand-out candidate for man of the match.
Biggest gaffe
Several players could lay claim to it after a host of excellent chances were missed by both sides, in both halves, but it has to be Ramsey, who volleyed over the bar from roughly six yards out in the first half. Honourable mention to Ighalo, who really should have fired the hosts ahead afterwards, but it was not a worse miss than the Welshman's effort.
Referee performance
Jones may find himself the target of some criticism by Flores - whether it is warranted or not. Moments before Arsenal opened the scoring, Capoue saw his penalty appeals turned down at the other end, with Jones dismissing them out of hand. To his credit, though, the official looked to have made the correct call.
What's next?
Watford: Flores and co are back in action next Saturday for the trip to Stoke City.
Arsenal: The Gunners, meanwhile, turn their attention toward Bayern Munich now in a must-win Champions League clash at the Emirates on Tuesday.