- Granit Xhaka's deflected shot puts Arsenal ahead.
- Danny Welbeck plunders home a header to double the advantage.
- Arsene Wenger claimed first win over Jose Mourinho at 13th time of asking.
- Gunners are sixth, six points off the top four with a game in hand.
- Manchester United's 25-game top flight unbeaten record ended.
- Recap: Liverpool 0-0 Southampton
Well that is all we have time for on this Premier League live text.
We're back tomorrow night with Chelsea vs Middlesbrough as Antonio Conte's side aim to strengthen their grip on the title.
But until then, it's a very goodbye.
Full time: Arsenal 2-0 Manchester United
Arsene Wenger claims his first competitive win over Jose Mourinho at the 13th time of asking as Arsenal boost their Champions League hopes. Manchester United are probably playing for fifth now but they still have the Europa League as a fall-back. Granit Xhaka and Danny Welbeck were the difference with two goals in the space of four minutes.
McTominay shoots via, Rooney's deflection but Cech saves. Probably the last chance.
Rashford skins Hector Bellerin but it is Aaron Ramsey who gets a foot in. Arsenal are going to run out comfortable winners here.
Laurent Koscielny has been superb today and he prevents United getting one back when he clears Martial's cross, with Lingard prowling.
Some people have Sunday lunch to get to.
Scott McTominay on for his Manchester United debut for the final six minutes. He replaces Juan Mata.
Rooney again from range and again he misses the target. Three chances for the United skipper this afternoon and no goal for the skipper. On the ball he has looked laboured at best.
Coquelin replaces Xhaka with 15 minutes to go. A change that may have happened anyway, but enforced through injury. The Gunners go to Southampton on Wednesday.
Wayne Rooney curls wide and over Cech's goal in United's best opening for some 10 minutes. Granit Xhaka down for Arsenal to slow play down a little.
Mesut Ozil whips the ball across the six-yard box but it just evades Welbeck.
Petr Cech continues to win his duel with Rooney, pushing away his free-kick. Arsenal clear the subsequent corner.
United's 25-game unbeaten Premier League run is coming to an end unless they can turn this around. Marcus Rashford is on now with Ander Herrera replaced.
Danny Welbeck powers a header to down the lead.
Two changes on the hour mark for Manchester United as they search for a way back into this game. Jesse Lingard on for Henrikh Mkhitaryan, while Marcus Rashford's introduction is also imminent.
David de Gea is helpless as Arsenal take the lead through Granit Xhaka.
GOAL! Arsenal 2-0 Manchester United (Danny Welbeck)
Two goals in the space of three minutes puts Arsenal firmly in charge. Oxlade-Chamberlain crosses brilliantly and Welbeck rises and thumps a header in off the crossbar and beyond De Gea. Fine goal and the hosts have a firm grip of this game.
GOAL! Arsenal 1-0 Manchester United (Granit Xhaka)
A game badly in need of a goal gets one in fortuitous circumstances. Granit Xhake lines one up from fully 30 yards and it takes a huge deflection off Herrera - who had turned his back on the ball - and it loops over David de Gea.
Really sluggish start to the second half. Not what we needed after the first end began to meander towards the end.
A message from the travelling Manchester United support.
Back underway at The Emirates. Some goals, please.
Players out for the second half in north London. Arsenal have been level at the break in their last two home games before going on to win. Can they make that three in a row?
Nearly ready to resume at The Emirates. It has not been a classic afternoon of Premier League football. No goals in one-and-a-half games. Surely it can only get better?