By Chris Harris at Emirates Stadium
Arsenal were left to rue their luck after losing a game they deserved to win against Manchester United on Saturday.
Arsene Wenger's side dominated the first half but squandered a golden chance to take the lead when the impressive David De Gea denied Jack Wilshere.
The home side paid for their below-par finishing in the second half when Kieran Gibbs, grounded after a collision with Wojciech Szczesny, diverted Antonio Valencia's shot beyond his stricken goalkeeper.
An injury to Wilshere compounded Arsenal's woes and, although they fought gamely to get back into the match, United struck again five minutes from time when Wayne Rooney broke away to beat substitute keeper Emiliano Martinez.
Eight minutes of stoppage time gave the Gunners a glimmer of hope and they set up a grandstand finish when Olivier Giroud marked his return from injury with a thumping shot to finally beat De Gea.
But time ran out for Arsenal, much as their luck had done earlier in the half.
SETTING THE SCENE
At the turn of the century, these teams were THE big two in England, but the backdrop to this game was rather different from those Vieira-Keane days - Arsenal in seventh, United ninth and both sides needing a win to reestablish their credentials.
All the same, the noise levels at Emirates Stadium served as a reminder that this remains a landmark fixture in the football calendar.
Wenger made two changes for his first Premier League tussle with Louis van Gaal. Santi Cazorla and Mathieu Flamini made way for Wilshere and Mikel Arteta, the latter fit after a hamstring problem.
Former United striker Danny Welbeck started against his old club and on the bench sat Giroud, back ahead of schedule after a broken tibia. Theo Walcott was ruled out by a slight groin injury.
The United side featured an inexperienced back three, a stellar summer signing in Angel Di Maria, and a pantomime villain - former Arsenal captain Robin van Persie.
Roared on by a vociferous home crowd, Arsenal started on the front foot.
Alex Oxlade-Chamberlain had a better international break than most and he led the charge. One drive into the box in the fifth minute set up a chance for Welbeck, but he couldn't make proper contact.
Welbeck made a better fist of his next half-chance, nodding over the bar after Oxlade-Chamberlain delivered an excellent cross from the right.
Wilshere was allowed to run through the centre in the 13th minute but his low shot was straight at De Gea. The United goalkeeper got down to his left to deny Welbeck seconds later.
Now it was all Arsenal and a glorious chance went begging in the 16th minute. De Gea's poor kick was seized upon and Welbeck played in Wilshere. He raced through on goal but couldn't beat De Gea from close range.
United, beaten only once in their last 14 matches against Arsenal, looked there for the taking.
Wayne Rooney fired a free-kick over the bar after 21 minutes but it was a rare foray into Arsenal territory. And De Gea was soon called into action again, smothering well when Oxlade-Chamberlain tried to wriggle past him inside the box.
This was a great advert for the Premier League - fast, flowing and fiercely-contested. Arsenal sensed blood and the noisy Emirates crowd responded.
De Gea was called upon again when Alexis worked a yard of space 20 yards out and fired in a low shot that the keeper held well.
At the other end Di Maria curled a shot wide and Rooney was denied by a fantastic challenge from Calum Chambers, but this had been Arsenal's half.
The second half began as the first had ended - with Arsenal on top. Oxlade-Chamberlain saw a shot deflected wide before finding Welbeck with a searching pass. The forward raced beyond Paddy McNair but was denied by De Gea.
Then, in the space of a couple of minutes, miserable luck hit Arsenal hard.
Wilshere was left clutching his ankle after McNair's sliding challenge and was eventually replaced by Cazorla. Worse was to follow in the 56th minute.
A hopeful cross towards Marouane Fellaini saw Szcznesy and Gibbs challenge for the high ball. They collided in mid-air and fell to the ground, the loose ball was smashed goalwards by Valencia, hit a prostrate Gibbs and flew into the net.
To compound Arsenal's misery, the injured Szczesny could not continue. Martinez replaced him.
Arsenal had half-an-hour to rescue a game they had done enough to win. Typically, Alexis was at the heart of their response, flashing in a header that De Gea held.
Alexis fired a free-kick over the bar and Wenger played his final card when Giroud was brought on 14 minutes from time. He almost had an immediate impact, heading an Alexis corner just over the bar.
United seemingly made sure of the points when Di Maria found Rooney on the break and he beat Martinez with a clever finish.
Eight minutes of stoppage time and a fine strike from Giroud set up a frantic finale - but Arsenal could not find an equaliser.
Referee: Mike Dean
Copyright 2018 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source.