Jesse Lingard fired Manchester United to a pulsating 3-1 victory over Arsenal that cut Manchester City's lead at the top of the Premier League to five points on Saturday.
Jose Mourinho's side struck twice in the first 11 minutes at the Emirates Stadium as Antonio Valencia and Lingard punished suicidal Arsenal defending.
Alexandre Lacazette reduced the deficit, but United goalkeeper David De Gea made a series of superb saves before Lingard grabbed his second goal.
Despite the late dismissal of United midfielder Paul Pogba, who will miss next weekend's Manchester derby after a nasty challenge on Hector Bellerin, the visitors held on for a priceless victory.
United's fourth successive league win puts pressure on City to maintain their blistering form against West Ham on Sunday.
Regardless of City's result, United's first victory at the Emirates since November 2014 keeps them in the title hunt ahead of their seismic showdown with the leaders.
For Mourinho, this was a cathartic result as United earned their manager -- who had been criticised for his cautious tactics in big games -- a first away league win against a top-six rival in 12 attempts.
It also extended his mastery over Arsenal boss Arsene Wenger, who has now won only two of their 19 meetings.
The end of Arsenal's 12-match winning run in home league games left their already faint title hopes in tatters.
They trail 12 points behind City after dropping to fifth place.
Wenger this week admitted that Arsenal's meetings with United no longer carry the same prestige they did when the Gunners were slugging it out for the title with Alex Ferguson's teams.
That may be the case with City in the ascendency, but this was still a classic encounter.
Mourinho's side took the lead in the fourth minute when Valencia intercepted Laurent Koscielny's loose pass and picked out Pogba on the edge of the Arsenal area.
Nacho Monreal failed to spot that Valencia had carried on his run and Pogba slipped the ball to the Ecuador defender, who drilled a clinical finish past Petr Cech.
If that was a self-inflicted wound, there was worse to come as United doubled their advantage in the 11th minute.
- Lethal raid -
Shkodran Mustafi carelessly surrendered possession deep inside his own half and Lingard pounced, teeing up Romelu Lukaku, who sent Anthony Martial scampering into the Arsenal area.
Martial steered a deft pass into Lingard's path and the United winger kept his cool to shoot low into the far corner for his fifth goal of the season.
Arsenal weren't ready to surrender and they should have been back in it when Lacazette took aim from close-range, only to see his shot blocked onto the bar by De Gea before Granit Xhaka smashed the rebound just wide.
After Ashley Young headed Mesut Ozil's free-kick off the line, the inspired De Gea made a brilliant one-handed save to stop Lukaku's miscued clearance ending in an own goal.
Arsenal's sustained pressure was finally rewarded in the 49th minute.
Alexis Sanchez chipped a pass into the six-yard box and Aaron Ramsey volleyed back to Lacazette, who fired home for his eighth goal of the season.
Lingard almost produced the perfect response for United, but Cech saved and the ball bounced to safety off the bar.
United were still creaking at the back and De Gea had to produce a miraculous double save to preserve their lead.
Diving to his right, he stopped Lacazette's strike before somehow reacting quickly enough to block Sanchez's follow-up with his boot.
That incredible escape was the signal for United to make Arsenal pay with a killer third goal in the 63rd minute.
The incisive raid reached a fitting crescendo when Lukaku sent Pogba into the penalty area and his low cross found Lingard unmarked to tap in at the far post.
The drama wasn't over as Pogba saw red in the 74th minute for his crude studs-up foul on Bellerin.
But with De Gea in defiant mood, United had done enough for a memorable success.